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https://archive.org/details/outlineofscience04thom 


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“DAQUDZ 2 IWJadda NT XQ YFdASOIOYG D UWOAL 


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THE 
OUTLINE OF SCIENCE 


A PLAIN STORY SIMPLY TOLD 


EDITED BY 


J. ARTHUR THOMSON 


REGIUS PROFESSOR OF NATURAL HISTORY IN THE 
UNIVERSITY OF ABERDEEN 


WITH OVER 800 ILLUSTRATIONS 


OF WHICH ABOUT 40 ARE IN COLOUR 


IN FOUR VOLUMES 


KO KOK 


G. P. PUTNAM’S SONS 

NEW YORK AND LONDON 

The Rnickerbocker Press 
1922 


Copyright, 1922 
by 
G. P. Putnam’s Sons 


Per 


New York, 


Made in the United States of America 


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CONTENTS 


XXVII. Bacreria. By Sir E. Ray LANKESTER 
The Early Microscopists—Leeuwenhoek’s Work—O. fF. 


Miiller’s Work—First Use of the Name Bacteria—Abiogen- 
esis—“Spontaneous Generation’—A Long Controversy— 
Closer Study of Infusions—The Bacteria Removed to the 
Vegetable Kingdom—Pasteur’s Early Discoveries—The 
Steps Leading to our Present Knowledge of the Bacteria 
—Forms of Bacteria—Multiplication and Movements—The 
Jelly Phase—Reproduction of Bacteria—Protoplasm of 
Bacteria—Influence of Moisture Desiccation—Influence of 
Heat and Cold—Influence of Light—Influence of Gravity— 
Influence of Chemical Agents—The Action of Bacteria on 
their Surroundings and especially on Organic Matter—Fer- 
ments—Putrefaction—Circulation of the Organic Elements 
—Species of Bacteria—Manifold Activity of Bacteria— 
Luminous’ Bacteria—Disease-carrying Bacteria—Bacteria 
Causing Disease—How Bacteria are ‘“Carried’”—Bacteria of 
the Soil—Sewage as Manure and as Pollution. 


XXVIII. THe Maxine oF THE EARTH AND THE 


STORY OF THE Rocks 


Origin of the Earth—The Interior of the Earth—Distribution 


of Land and Water—Volcanoes—Vesuvius in Eruption— 
Earthquakes and Geysers—The Making of Mountains—The 
Making of the Alps—The Mountains of Scotland—The De- 
struction of Mountains—A Piece of Granite—Crystal Mak- 
ing—A Piece of Sandstone—A Piece of Coal—A Piece of 
Chalk—The Building of a Coral Island—A Piece of Slate— 
Precious Stones—Pearls—Aristocrats among Jewels—The. 
Diamond—Remarkable Histories. 


XXIX. THE SCIENCE OF THE SEA 
The Making of the Sea—Why is the Sea Salt?—The Depth 


of the Sea—Temperature of the Sea—Pressure in the Sea— 


lil 


510522 


PAGE 


865 


917 


957 


iV 


Contents 


Movements of the Sea—Circulation in the Sea—Storms at 
Sea—The Floor of the Sea—Deep-sea Deposits—The Life of 
the Sea—The Bacteria of the Sea—Colour of the Sea—lIce 
in the Sea—The Uses of the Sea—The End of the Sea— 
Denizens of the Sea—Open-sea Animals—Marine Birds— 
Fishes in the Open Sea—Deep-sea Animals—Seashore 
Animals. 


XXX. ELectric AND LUMINOUS ORGANISMS 


Luminous Plants—Luminous Animals—Faraday’s Contribution 


—The Nature of Animal Light—The Fire-fly’s Light Excels 
all Human Devices—Different Colours of Animal Light— 
Different Modes of Light-Production—When the Dredge 
Comes Up—The Illumination of the Sea—Possible Uses of 
Animal Lights—Animal Heat—Animal Electricity: Electric 
Animals; the Electric Ray; the Electric Eel; the Electric 
Catfish; Biological Conclusion. 


XXXI. Natura, History. V.—THE Lower 


VERTEBRATES 


The Essential Characters of Vertebrates—The Pioneers—The 


Sea-Squirts—The Lancelets—The Round-Mouths—Fishes 
—Amphibians—Reptiles—Tortoises and Turtles. 


XXXII. THe Ernstern THEORY 
Are Things What they Appear?—A New View of Gravity— 


The Curvature of Space—The Theory of Relativity—The 
Fourth Dimension—The Test of Experiment—Turning Time 
Backward—Space and Time Blended Together—The Great 


Prediction. 


XXXIII. THe BrioLocy oF THE SEASONS 


The Rhythm .of Life—Ripple-marks of Growth—I. The 


Biology of Spring: Animals Reawaken; the Story of Lam- 
preys; the Eel-fare; the Return of the Birds—II. The 
Biology of Summer: Intense Activities of Summer; Industries 
of Animals; Birds’ Nests; Parental Care—III. The Biology 
of Autumn: Autumn Fruits; the Scattering of Seeds; Wither- 
ing Leaves; the Work of Earth-worms; Flights of Gossamer; 
Preparations for Winter; the Story of the Lemmings—IV. 
The Biology of Winter: Winter Whiteness; Lying Low; 
Winter Sleep; Condensation into Small Bulk; Migration; 
Reduction of Numbers; Elimination. 


PAGE 


989 


1009 


1023 


1043 


Contents 


XXXIV. Wauat ScrenceE MEAns For Man. By 
Sir Oxtver LopcEr 


The Aim of Science—Outlook on the World—Evolution of 
Mind—Beauty and Truth—Relation Between Life, Mind, 
and Matter: Life, Mind, and Will—Nature of Life—The 
Essence of Mind—Matter the Vehicle of Mind—Grades of 


Incarnation. 


XXXV. ETHNOLOGY ; 


One Species with Many Races—The Primary Groups of Man- 
kind—A Change of Outlook—Hormones and Ethnology— 
The Making of Races—Ethnology and Population—Must 
Races Decline? 


XXXVI. THE Story or DoMESTICATED ANIMALS 


Horses—British Breeds—The Arab—Cattle—Sheep—Goats— 
Pigs—Dogs—Selection in Breeding—Cats—Rabbits—Ele- 
phants, Camels, and Llamas—The Taming of the Birds. 


XXXVII. THe Science or HEALTH 


What is Health?—Health as Working Capacity—The Energy 
of Food—Proportions of Different Kinds of Food—Im- 
portance of Vitamins—Enjoying Food—Muscular Develop- 
ment May be Exaggerated—Exercise—Happiness Correlated 
with Health—Respiration and Circulation—The Breath of 
Life—The Body Temperature—The Climate under the 
Clothes—Open Air and Light—Sleep—Mental Hygiene— 
Bacteria, the Fruitful Source of Disease—Artificial 
Immunity. 


XXXVIII. Screncret anp Mopern THoucHT. By THE 
} LODITOR@ tea ue A ; 


The Aim of Science—The Scientific Mood—The Methods of 
Science—Scope of Science—Classification of the Sciences— 
Limitations of Science—Science and Feeling—Science and 
Religion—Science and Philosophy—Science and Life. 


CLASSIFIED BIBLIOGRAPHY 


INDEX 


1091 


1105 


1131 


1163 


1183 


1197 


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ILLUSTRATIONS 


Vesuvius InN Eruption : : ‘ Coloured Frontispiece 
From a photograph by Negrete & Zambra. 


Tue “Ceiis” or CELLULAR STRUCTURE OF Cork, AS SEEN IN A THIN 


Suice MaGeniriep 200 DIAMETERS é : : : f A : 
From Robert Hooke’s Micrographia. 


SEcTION THROUGH VEGETABLE TissuE SHOWING HEXAGONAL CELLS EN- 
CLOSING ‘“PRoOTOPLASM ’. : : : ; : : ; 


CoLuMNAR CELLS FRINGED WITH VIBRATING “‘CiLIA”” AND Eacu Con- 
TAINING A “NucCLEUS” : , , é 2 ; : 


Tue ANIMALCULE Known as Euplotes harpa . : : : 


Drawincs oF ANIMALCULES BY EHRENBERG : : 
From Plate V. of Ehrenberg’s Infusionsthierchen bose 1838). 


Tue Vinegar FermMent or Acetic Bacterium (Bacterium aceti) ; 
Various Forms AssuMED BY THE BacTeriaAL “Unir’ on Puastip . 
Groups or Micrococcr More or Less CLosEty AGGREGATED : 


BRANCHING GROWTH OF THE BacTERIuM CaLuLepD Cladothrix dichotoma, 
Livine 1n River WaTER . 


Various GrowtH-Forms or Cladothriz dichotoma or Zorr—a ‘“‘PLEo- 


MORPHIC or “Many SHAPED” BacTERIUM : : . i 
From Zopf, Die Spaltpilze, Breslau, 1885. 


Part oF AN ARBORESCENT JELLY-Mass oR Ca@noGu®A, ForRMED BY 
Cladothriz dichotoma : ; ; : , ; : " ; 


PLEOMORPHISM OR VARIETY OF GrowTH-ForMs SHOWN BY THE Bacterium 


merismipedioides : ; : ‘ ° ‘ : 5 : : 
Tue Livine Bacituus oF TypHorp Fever . . : ; : . 


Livina SPIRILLA FROM A Drop oF SEWAGE-WATER : : : 4 


vil 


FACING 


870 


870 


870 


871 


871 


876 


876 


877 


St, 


882 


882 


883 


888 


888 


Vill Illustrations 


Tue “Hay-Baciiuus,” Bacillus subtilis, or CoHN AND SUBSEQUENT 
WRITERS. : : g ; : ; : : : : 


DeepLy STAINED Preparations MaprE iN OrpDER TO SHOW THE Various 
Forms or CiLiaA AND THEIR ARRANGEMENT IN DIFFERENT KINDS 
or BAcTERIA F : . . : ‘ : ; : . 


Mesuwork LIKE THAT OF THE GREEN FRESHWATER ALGA HyprRopICTYON 


Tue Biscurt-SHAPE or Figure-or-E1GHT PRoDUCED BY AN INCOMPLETE 
Division oF A SPHERICAL oR Coccus Form : , . ; : 


Tue Patruocenovus Bacterium wHIcH Causes PNEUMONIA (FROM THE 
Lune or a Movse) : é : ; : ; 4 4 


Leuconostoc mesenteroides (Cienkowski)—Tur ‘“Froe’s Spawn” 
GrowTH . : 4 : : . : : : ' 


ZOoGL@A OR C@NOGL@A, oR JELLY-Mass Formep By a BacTerium 
GROWING ON A SLICE OF CaBBAGE Root . : J : ’ 


Various Forms or JELLY-LIKE Massres (“Zoocira@a or “Canoeiraa”) 
Propucep By ENcLosep BacrTeria . : : - : : 


A FracMent or “THe GInGEeR-BEER PLANT’ : 3 : 


Bacillus anthracis, THE PARASITE OF MALIGNANT PustTuLE or Woo L- 


Sorter’s DisEasE (AFTER Rogsert KocwH) : : : ; ° 


Tue Firamentous GrowrTus oF Bacillus anthracis PRopucED By CULTI- 
VATION OUTSIDE THE ANIMAL Bopy Become SeEptate, aND Eacu 
SecmMent Gives OriGIN To aN OvaL Sratospore (or “ENDURING” 
SPORE) A : : : : : ‘ ; ; ; : , 


Vibrio rugula, A FERMENT OF VEGETABLE SUBSTANCES, DissOLVING THE 
Fisre-FORMING CELLULOSE OF THEIR Harp Parts . 5 ' . 


Spirillum obermeieri, THE Cause oF RELAPSING FEVER . : ; : 


Ture ANIMALCULE AMG@BA AND A PHAGOCYTE OR COLOURLESS CORPUSCLE 
OF THE VERTEBRATE’S BLoop CoMPARED 2 : 4 ; : : 


Tue INVASION OF THE Roots oF THE PEA AND Bean Famivy BY Bacteria 
Tue CHOLERA SPIRILLUM, oR Comma-Baci.tuus oF Kocu ? é . 


Tue Bacillus tuberculosis or Kocu f ' ¢ ‘ 2 ‘ 


FACING 
PAGE 


888 


889 


894 


894 


894 


895 


895 


900 


901 


901 


901 


906 


906 


906 


907 


907 


907 


Illustrations 


A San Francisco PaveMENT Torn BY THE EARTHQUAKE 
Photo: Underwood & Underwood 


Tue Errect or an EarTHQUAKE IN JAPAN 
Photo: E. N. A. 


Tue Ruinep Biwasima Brince Across THE River SHONIGAWA, JAPAN 
Photo: E. N. A. 


THE SEISMOGRAPH . : 
By courtesy of Messrs. R. We Mineo Ltd. 


Tue Himatayas, SHow1na Mount EvEREsT 
Photo: L. E. A} 


MarINE EROSION ON THE IRISH COAST 
Photo: W. A. Green, Belfast. 


ArTHUR’s SEAT, EDINBURGH . ‘ : ‘ : Lu . 
Photo: Valentine. 


Fincau’s Cave, STAFFA . : ; : ; : 4 : 
Photo: James’s Press Agency. 


Cox’s Caves, CHEDDAR, SOMERSETSHIRE : : : : : 
Photo: H. J. Shepstone. 


Waimanau Geyser, Near Rororva, New ZEALAND. 
By permission of the New Zealand Government Office. 


Five Straces In THE Maxine or A Mountain CHAIN 
Diagram SHowi1na Tyrrs or Mountains 


GIANTs OF THE PENNINE ALPS 
Photo: A. Landsborough Thomson. 


THe MarrerHORN ’ : ; ! 3 : 
Photo: A. Landsborough Thomcr 


A Typicat GLACIER VALLEY : ; ; : : : 
Photo: A. Landsborough Thomson. 


Tue GornNeER GLACIER . ; ; : . d 
Photo: A. Landsborough THCcont 


EvipENcE or GuaciaAL ACTION 4 ; ’ ; t : 
Photo: W. A. Green, Belfast. 


Tue Giant’s Causeway, County ANTRIM, SHOWING THE GRAND CavusE- 


WAY . . . . . ° . a ° ° ° 
Photo: W. A. Green, Belfast. 


Tue Pueraskins, Giant’s CAUSEWAY : ; ; 
Photo: W. A. Green, Belfast. 


ix 


FACING 
PAGE 


920 


921 


921 


924 


924 


925 


925 


926 


927 


930 


931 
931 


932 


933 


936 


937 


938 


939 


939 


x Illustrations 


A Mass or AMMONITE SHELLS 
Photo: W. A. Green, Belfast. 


A Fossin SPECIMEN 
Photo: W. A. Green, Belfast. 


“Fosstr HorsEtraiLts” or CALAMITES 
Photo: J. J. Ward. 


Fossir PLANtTs oF THE Coat MEASURES 
Photo: W. A. Green, Belfast. 


Tue Cuirrs oF DoveR 
Photo: Topical Press Aeeney. 


A Corat REEF 
From the amitheentil Perort. 1917. 


Tue Castes or Kivvirar, Mourne Mountains, IRELAND 
Photo: W. A. Green, Belfast. 


A State Quarry (Dinowrir) 
Photo: Topical Press Agency. 


Precious Stones (Coloured Illustration) 


Reproduced by courtesy of Methuen & Co., Ltd. ont Chl Ponte by 
G. F. Herbert Smith. 


DEscENT TO THE D1amMoNp MINEs, KIMBERLEY 
Photo: H. J. Shepstone. 


SorTING THE GRAVEL FOR DIAMONDS AT THE KIMBERLEY MINES 
Photo: H. J. Shepstone. 


His Serene Higuness ALBert, Prince or Monaco (b. 1848) 
Photo: Copyright, Daily Mail. 


Tue Late Sir JoHN Murray 
Photo: Elliott & Fry, Ltd. 


A New Wor.tp For THE LANDscAPpE PAINTER—AT THE BoTToM OF THE 
Sra—Has BEEN OPENED UP BY AN Artist, Mr. Zaru PritcHarp, WHo 


Paints Unper Water 1N Divina Dress 


Reproduced by courtesy of the purchaser, the Prince of Vganetae ta the 
artist. 


Hert Bay, Scitty Istes (Coloured Illustration) 
Photo: Frith & Co. 


ANOTHER SUBMARINE “LANDSCAPE, SHOWING A BasaLT TUNNEL ON THE 
Sra-Bep 


Reproduced by tontesy of the artist ang the Galeries Geeta Petit, Paris. 


At CapstonE Hix, ILFRAcoMBE 
Photo: L. E. A. 


FACING 
PAGE 


942. 


943 


943 


946 


947 


948 


948 


949 


950 


952 


953 


962 


962 


963 


966 


968 


969 


Illustrations Xl 


FACING 
PAGE 


Tue Guur Stream HAs CLEARLY DEFINED “Banks” oF WaTER . . 974 


A WaTERSPOUT : : p ; : ? : ; ? : . O74 
Photo: J. W. Knight. 


Derp-seEA Deposits; THE SHELLS OF Minute Creatures, KILLED aT THE 
SurFAcE, SUNK INTO THE OOZE oF THE OcEAN FLOoR ; Pit ees: 


An ENLARGEMENT OF A YouNG Form oF an AsyssaL FisH (SivyLopu- 


THALMUS) FROM VERY Derep WatTeER IN THE INDIAN OcEAN .. eee 
AN IcEBERG .. : : : 980 
Photo: The Holloway Studio, Ltd. 

A Corau FisH : ; d : : : : : : : . 980 
A Froatina Barnac Le : : d : y x “ : EYS1 
Reproduced by courtesy of Messrs. Andrew Melrose, Ltd. from The 

Haunts of Life, by Professor J. Arthur Thomson. 
Tue Fioor or THE DEEP SEA ‘ : ; : : : eos! 
Reproduced by courtesy of Messrs. Andrew Melrose, Ltd., from The 
Haunts of Life, by Professor J. Arthur Thomson. 
A Derrp-sea ScENE (mostly after Chun) : ; : : . 994 


A RemarkaBLe Luminous Fisu, Lamprotoru flagellibarba, rrom Drep 
WaTER OFF THE SOUTH-WEST OF IRELAND. (After Holt and Byrne) 995 


Luminous Deep-Sea ANIMALS FROM THE Mip-Atiantic (Coloured Illus- 


tration ) : : : 996 
From Professor Doflein. 
A View 1n A Surrey LANE, WITH THE HepGe-Banks LIT uP BY GLow- 
WorMS THAT HAVE CLIMBED THE HERBAGE ‘ : ‘ : . 998 
Tue Evectric Cat-Fisu : 4 : ; : : : : . 998 
Two Deep-Sea FisHEes (FROM THE PRINCE oF Monaco’s Memoirs) . 999 
A Fire-Fiy . : : : ‘ : : : : : : . 999 
A Maeniricent Luminous Sea-Pen (ANTHOPTILUM), ABOUT A YARD 
Hiau, rrom Derr WaTER OFF JAPAN : , , . : . 1002 
A Sma. Execrric Ray, Torpedo ocellata, FRom THE MEDITERRANEAN, 
SHOWING THE DorsAL SURFACE : : , : ; . 1003 
Two Exectric FisHes . : : ‘ ; | } ' : . 1003 
A Fu. View or THE ANGLER’s TRAP <sihiia : ; : ; . 1014 


Photo: E. Step, F. L. S. 


xii Illustrations 


FACING 
PAGE 
Tue Proteus, or Omm . : : ; . . ' : ; . 1014 
Tue TUATERA : ‘ : : ; ; : F : . 1015 
Photo: W. S. Berridge. / 
INDIAN CROCODILE . . . ; : A a s ; : . 1015 
Photo: W. S. Berridge. 
Srorrep Turties FIGHTiIne ? : : 2 te : : LOLS 
Photo: James’s Press Agency. 
ELEPHANTINE TORTOISE ‘ : : ; : ‘ “ a . 1018 
Photo: James’s Press Agency. 
PytTHON ; : : é : : if : 4 : : . 1019 
Photo: James’s Press Agency. 
Tue Curve oF THE StTar-Ray SHows THAT SPACE Is CURVED IN PRESENCE 
oF Matrer (tHE Sun). Upon tuis Fact Ernstein’s THrory or 
Gravity 1s FouNDED ; ; : . ; ‘ y 5 . 1030 
Tue APPARATUS OF THE Famous MicHELSON-Mor.LEY EXPERIMENT . 1030 


A Surp at Sea Determinine 1ts Motion. (A CoMPaRISON WITH THE 
Famous Micureitson-Moriey Experiment CoNCERNING THE ETHER) 1031 


Diacrams ILLUSTRATING EINSTEIN’s THEORY : y : A PLOT 


ANNUAL Rines or GrowTH IN P1inNE-Woop . : : : . 1048 
Photo: J. J. Ward. 


One or THE Earuiest FLowers oF SPRING ‘ ; ; : . 1049 
Photo: John J. Ward. 


LEAFING AND FRuITAGE oF THE HorsE-CHESTNUT . : . 1054, 1055 


Snaits “‘Larip uP”? FoR THE WINTER ON A SHELTERED WALL . . 1060 
Photo: J. J. Ward. 


Insects at Rest . : : : ‘ : : : : : LOGO 
Reproduced by permission from The Wonders of Instinct, by J. H. Fabre. 


Two Ants SHEPHERDING GREEN-F LIES oR APHIDES 2 : ‘ . 1061 
Photo: J. J. Ward. 


Huntine Spwer (Dolomedes mirabilis) Carryinac A S1tKen Eae- 


Cocoon : : ; E , : A : : : : . 1061 
Photo: J. J. Ward. 


Tuer Expiosion oF THE Broom Pops . é / ; ; ; . 1064 
Photo: J. J. Ward. 


Fruiting Heap or tHE Witp Trasex (Dipsacus Sylvestris) . , . 1064 
Photo: J. J. Ward. 


WINTER i er ear : . ‘ y , ‘ : 5 . 1065 


Illustrations 


SUMMER é : , 
Photos: S. Leonard Bastin. 


Tue BLappERWoRT oR UTRICULARIA 
Photo: J. J. Ward. 


Micuart ANGELO IN His Srupio 
Joun Keats 

BEETHOVEN 

Joun RuvuskIN 


GoETHE 


J. M. W. Turner, R. A. 
Photos: Rischgitz Collection. 


DANTE 


Tue Rep “Inp1an” (Coloured Illustration) 


A Maori : 
Photo: E. N. A. 


ZuLu : : : 
Photo: H. J. Shepstone. 


Hinpvu : ; : : : 
Photo: Bourne & Shepherd, India. 


ARAB : : : 
Photo: H. J. Shepstone. 


JEW : ‘ ; : 
Photo: H. J. Shepstone. 


A CanTONESE GENTLEMAN 
Photo: E. N. A. 


A Typicat Eskimo 
Photo: E. N. A. 


Monaouran Witp Horse 
Photo: F. W. Bond. 


SHETLAND Pony 
Photo: Charles Reid. 


ARAB STALLION : 
Photo: W. A. Rouch. 


Persimmon (taken immediately after winning the Derby, 1896) 
Photo: W. A. Rouch. 


xii 


FACING 
PAGE 


are 


POLO TL 


. 1080 


2 208% 


. 1081 


. 1084 


. 1084 


- 1085 


. 1085 


. 1094 


- 1098 


- 1098 


. 1098 


. 1098 


« LO9Y 


772099 


L099 


. 1108 


. 1109 


. 1109 


mca 6 


X1V Illustrations 


HIGHLAND Cows . ‘ : < 
Photo: Charles Reid. 


A DomesticaTeD Form oF THE WiLtp Yak, FouND ONLY IN THE Ruspu 


PLATEAU 
Photo: F. W. Bena 


WatiacnHian Ram ; 
Photo: British Museum CN auiral Eastory) 


Soa (Soay) Ewes, Sr. Kitpa : 
Photo: British Museum (Natural History) 


Four-Hornep Manx Loaeutan Ram 
Photo: British Museum (Natural History) 


Unicorn Barwat Ram, Nepau, Inp1a 
Photo: British Museum (Natural History) 


Tue MastIFF be : é . : E , ‘ : 
Tue Buiipoag 

Tue Scots Drer-Hounp , ; e ; : : : 
Tue Wrire-Hairep Fox-Terrier . ‘ : : 

Tue Brioop-Hounp : : : : : 


Photo: Sports and General. 


Tue Cocker SPANIEL . 
Tue Evotution oF Domesticatep Pigeons (Coloured Illustration) 
Tue Use or THE Foop-STuFFs IN THE Bopy 


Proressor F. Gowranp Hopkins, F.R.S. 
Photo: Palmer Clarke. 


Proressor J. ArTHUR ‘THOMSON ’ fh 


Tur Composition or Certain Common Foops (Coloured Illustration) 


Sir Freperick Treves, Bart., G.C.V.O. 
Photo: Bacon. 


Tue Late Sir Witiiam Oster, Bart. 
Photo: J. Russell & Sons. 


Screntiric Motion Stupy—1 
From Report No. 14, Thousteal Pati rue Researen Botrdl 


Screntiric Motion Stupy—2 
From Report No. 14, Industrie Pate Reach Board 


FACING 
PAGE 


ra 8 Re 


. 1113 


LLG 


Pe hi baits" 


LL 17, 


rd OG Bre 


. 1120. 
. 1120 
. 1120: 
eLLZh 


eh Ova 


a LEA 
. 1124 
. 1134 


- 1135 


Ae © 315) 


1138 


. 1144 


. 1144 


. 1145 


- 1145 


Illustrations XV 


FACING 
PAGE 


PHoTOGRAPH oF A LEAF FROM A City TREE (LEEDs) é : Say. 


Photograph: J. B. Cohen, F.R.S. From Special Report Nol 52, Medical 
Research Council. 


Puacocytes or WuitE Biroop Ce_its DEFEND THE Bopy From INVADING 


MIcROoBEs . : : . 1152 
Microphotograph: are Watt, Tene ard Behers: “Silicosis,” Bretorin 1916. 


Sir AtmrotH WriauHtT . : ; : f ; : 5 : ey M bass 
Photo: Russell, London. 


ALBERT EINSTEIN ; : s fs : : : J - - 1153 
Photo: Bennington. 


The Outline of Science 


XXVII 
BACTERIA 


By Sir EK. Ray LANKESTER 


VOL. IV—1 865 


F 
~ 


Rat. 


BACTERIA 


THE BACTERIA: THE UBIQUITOUS GERMS OF FERMENTATION, 
PUTREFACTION, AND DISEASE 


By Sir E. Ray LANKESTER 


The Early Microscopists | 
, \ HE microscope is the means by which our modern under- 


standing of the structure and nature of living things— 
as contrasted with the baseless fancies and blank ignor- 
ance of three centuries ago—has been gained. It is a noteworthy 
fact that even the use of a simple lens of glass or crystal as a 
magnifier is not recorded by ancient Greek or Roman writers 
—though it is difficult to believe that some of the minute engrav- 
ings on ancient gems were made without the use of a magnify- 
ing-glass. It is true that Pliny tells us of the concentration of 
the sun’s rays by a glass globe filled with water, and of the use 
of such a globe as a “burning glass”; but the first records we 
have of the use of glass lenses as optical instruments date from 
the early years of the fourteenth century, when they were used 
by ingenious Italians (some say by Roger Bacon also) to improve 
the failing sight of old people, and were (as they still are) called 
“spectacles.” In a portrait of Pope Leo X, painted by Raphael 
in 1520, the Pope is drawn holding a hand-magnifier, evidently 
intended to enable him to read the pages of a book open before 
him, 
It took two hundred years for learned men to advance from 
the use of “spectacles” to the first combination of lenses, to form 


on the one hand “a telescope” and on the other “a microscope.” 
867 


868 The Outline of Science 


The first-made “compound microscopes” or adjustments of two 
lenses—an “ocular” and an “object-glass”’ mounted in a tube, 
so as to give great magnifying power—were not so serviceable 
as a means of exploring the invisible world as were the cleverly- 
shaped single lenses, used by some naturalists. Robert Hooke 
—the secretary of the newly incorporated Royal Society of Lon- 
don—constructed in 1665 a compound microscope consisting of 
a cylindrical tube seven inches long, carrying eyeglass at one end 
and object-glass at the other; this was fixed by a ball and socket 
joint to a firm upright-support, and could be inclined at any 
angle. A screw arrangement for focussing and also elaborate 
illuminating apparatus were provided. Hooke’s microscope was 
an improvement in mechanism upon the Italhan instrument of 
twenty years earlier. One of these is attributed to Galileo, and 
was the first described. 

The main features of Hooke’s instrument, though the lenses 
have been greatly developed and improved, are retained in the 
latest compound microscopes of our own day. Hooke published 
a folio volume entitled Micrographia, describing his observations, 
finely illustrated by enlarged drawings of the flea, the louse, the 
house-fly, the nematoid worms called “vinegar-eels,” and of a 
variety of other objects. His drawing of the appearance of a 
thin slice of cork, greatly magnified, has become celebrated, since 
it is the first recorded observation of the cell-structure of plants 
(Fig. 1). The dried dead tissue, consisting of cell-walls enclos- 
ing air-spaces where once was living protoplasm, was compared 
by Hooke to the honeycomb made by the bees, the minute air- 
holding cavities resembling the closed “cells” of the honeycomb. 
Hence the word “cell” came into use for these universal units 
of plant-structure. 

A. century and a half later the word “cell” was applied, not 
to the empty-cell wall, but to its living viscid content by the 
founders of the “cell-theory” of organic structure and function, 
Schleiden and Schwann (see Figs. 2 and 3). We now speak of 


Bacteria 869 


the viscid content of the vegetable “cell” and of its equivalent 
in the structure of animals as “protoplasm.” 


Leeuwenhoek’s Work 

The early “compound” microscope, though giving high 
magnification, was of much less value as a means of discovery 
than might be supposed, owing to the distortion and want of 
clearness of outline in the magnified image which it gave. It 
was not at first better than, not even so good as, a single lens 
or simple microscope. In the later third of the seventeenth 
century Antony van Leeuwenhoek, a merchant of Delft in Hol- 
land, who has been called “the Father of Microscopical Dis- 
covery,’ made observations on “animalcules’—living in water, 
and in the interstices of his own teeth—with a microscope con- 
sisting of a single glass lens no bigger than a dried pea, ground 
into proper shape and curvature by himself, and mounted be- 
tween two perforated plates of silver. In 1672 he sent descrip- 
tions and drawings of his observations to the Royal Society of 
London—then recently founded. During fifty years, that is, 
from 1672 to 1722, fifty of his communications were published 
in the Philosophical Transactions. He was made a Fellow of the 
Society and received from it copies of its publications, including 
the book by Willoughby on Fishes, the cost of which caused such 
financial difficulty to the Society as to render it unable to under- 
take the publication of the Principia of Isaac Newton. 

Leeuwenhoek’s observations covered a wide field. They 
included the discovery of the red corpuscles of the blood of man 
and birds, the capillaries and the movement of blood along them, 
the spermatozoa of the dog and of the bird, the banded or cross- 
striped fibres of muscular tissue, the wheel-animalcules and their 
survival of desiccation and their “dispersal” as “dust,” the struc- 
ture of yeast as a mass of spherical corpuscles, and many other 
important things. It required no little skill and patience to 
make observations with the small simple lenses used by Leeuwen- 


870 | The Outline of Science 


hoek. Though definite facts were thus ascertained the optical 
imperfections of both the simple and the compound microscope 
were in these early days such as to give very incomplete and 
often erroneous notions of the things examined. 

Even after the lapse of a century, when O. F.. Miiller of Co- 
penhagen (born in 1730) described and figured with great skill 
the freshwater worms and other inhabitants of the ponds and 
streams of his native land, in publications which are still valued, 
the microscope was as yet so untrustworthy when high powers of 
magnification were used, that little value attaches to his draw- 
ings of very minute forms, though they are beautifully executed 
and engraved. He published in 1786 a volume entitled Animalia 
Infusoria—fluviatilia et terrestria, employing the name Infusoria 
(ever since retained in use with important limitations) for the 
first time for that population of swarming, struggling, multi- 
tudinous living things which, otherwise invisible, were revealed 
by the microscope in infusions of vegetable and animal deébris. 
Such infusions occur in natural waters or are purposely pre- 
pared in vessels and set aside for observation by the inquiring 
microscopist. 

Leeuwenhoek had already drawn attention to the minute 
living things thus revealed in their hundreds of thousands in 
“infusions” which he exhibited with his simple microscope to the 
Fellows of the Royal Society, to whom also he bequeathed a 
case containing twenty of his lenses. He wrote of the minute 
creatures discovered by him as “infusion-animalcules.”’ 

It is difficult to identify all the kinds described and figured 
by Leeuwenhoek with the comparatively feeble and “uncor- 
rected” (that is, “distorting’’) magnifying-glass used by him, 
and the consequent want of accurate detail in his figures. But 
the great successor of Leeuwenhoek and O. F’. Muller in this 
field of study—namely, Ehrenberg—writing in 1838, credited 
Leeuwenhoek with having distinguished twenty-seven kinds or 
“species” of Infusoria or “infusion-animalcules”; and O. F. 


From Robert Hooke’s ‘* Micrographia.” 


FIG. 1.—THE ‘‘CELLS’’ OR CELLULAR STRUCTURE OF CORK, 
AS SEEN IN A THIN SLICE MAGNIFIED 200 DIAMETERS 


(eye LE 
Levy ' ai 
‘ Hn 


FIG. 2.—SECTION THROUGH VEGETABLE F1G. 3.—COLUMNAR CELLS FRINGED WITH VIBRATING 
TISSUE SHOWING HEXAGONAL CELLS ““CRLIA,’’ ci, AND EACH CONTAINING A “NUCLEUS,” 7 


ENCLOSING ‘‘PROTOPLASM ”’ ; 
A, a row of such cells; B, a single ‘‘ciliated cell’’ detached 


a, cell-wall; b, protoplasm; c, liquid-holding from the others. 
space; d, nucleus or central ‘“‘kernel’’ in each 
cell. 


FIG. 4.—THE ANIMALCULE KNOWN 
AS Explotes har pa 


One of the larger ‘‘ciliated’’ Infusoria, 
provided with delicate cilia along the 
groov2 leading to the mouth and with 
coarse: leg-like outgrowths. The lower 
figure gives a side-view of the animalcule 
“running’’ on a piece of weed. 


From Plate V. of Ehrenberg’s ‘‘Infusionsthierchen”’ (Leipzig, 1838). 
FIG. 5 


The ‘‘species’’ are named by Ehrenberg as follows: 1 and 2, Bacterium triloculare (2 more highly magnified); 3, Bacterium enchelys; 
4, Vibrio lineola; 5 and 6, Vibrio tremulans; 7, Vibrio rugula; 8, Vibrio bacillus (what today would be called a Leptothrix form); 9 
Spirillum volutans ( X 300 linear); 10, Spirillum volutans ( X 800 linear); 11, less coiled examples of Spirillum. 


Bacteria 871 


Miller may be credited with a hundred more. Undoubtedly 
Leeuwenhoek saw some of the very abundant and excessively 
minute organisms which are now known by the name Bacteria, 
and described their characteristic movements. But he did not 
give any specific names to the forms which he described nor 


define them precisely. 


§ 1 
O. F. Miiller’s Work 

In the work of O. F. Miller a hundred years later the new 
influence and example of the great Linneus in introducing the 
use of generic with specific names and in systematising the 
nomenclature of living things had its effect. Muller distinguished 
and named the different “kinds” or species of Infusoria which 
he observed, and sorted the species so named into different 
genera. Kach genus so formed received a name and contained 
species which were held to be more like to one another than they 
were to the species of other genera. Thus he instituted a genus 
which he called “Vibrio,” and in this genus he placed several 
“species” which he had observed and of which he gives drawings. 
Thus we get his Vibrio lineola, V. rugula, V. bacillus, V. undula, 
V. serpens, and V. spirillum. ‘They are very minute, almost 
structureless, thread-like organisms which exhibit a darting and 
often an undulatory movement and locomotion. We can recog- 
nise them to-day by his drawings and still use his names for 
them. 

They comprise a large proportion of those organisms to-day 
known as Bacteria. But Miller was led, by a vague similarity 
in their shape, to name and enroll in his genus “Vibrio” a num- 
ber of other small (but not so very minute) worm-shaped crea- 
tures revealed by his microscope, which were really, as we now 
know (as the result of using improved microscopes), of more 
complex internal structure than, and remote in character from, 
his other species of Vibrio. Thus he reckoned as forming species 


872 The Outline of Science 


of this genus young thread-worms of the sort known as Nema- 
toids; also the wonderful organism which we to-day call by the 
name given to it by Ehrenberg, “Bacillaria paradoxa,”’ and other 
minute plants—now familiar to “pond-naturalists” as Desmids 
and Diatoms— besides the swan-necked animalcule called 
Trachelocerca! 

This genus Vibrio, with its strange mixture of species, was 
placed by Miller with four other genera, viz. Monas, Proteus, 
Volvox, and Enchelys, as the lowest or most simply organised 
group of the Infusoria. His genus Monas comprised four 
species—M. termo, M. atomus, M. punctum, and M. lens— 
very minute spherical forms, which it is not possible to identify 
to-day with certainty. Miuller’s genus Proteus contains the 
species of P. diffluens, which was described by other observers 
before him as “the Proteus animalcule.” It is to-day known as 
one of the species of the genus Ameeba. 

A second species named by Muller Proteus tenax, and 
admirably drawn by him in its changes of shape, is really a 
species of Astasia—a genus not known by name in Miiller’s day. 
Miiller assigned to a genus “Volvox” the well-known globular 
composite organism still known by that name and several other 
microscopic forms resembling it in general shape but now 
assigned to separate and widely separated genera. Under his 
genus Enchelys, Miller placed (and gave specific names to) a 
number of obscure forms which it is impossible to identify (from 
his drawings) with any of the microscopic forms which we know 
to-day. Of larger kinds of Infusorial animalcules Muller de- 
fined and carefully figured thirteen genera with a great number 
of species. Some of them are examples of the group of Protozoa 
which are to-day called the ‘“‘Ciliata,” because they are beset with 
vibrating filaments or hairs called “cilia” (see Fig. 3), and for 
these Ciliata the names used by him still are maintained, since 
his drawings leave no doubt as to their identity. 

Such are the well-known species of “Paramcecium,” of “Kol- 


Bacteria 873 


poda,” “Bursaria,” and “Vorticella,” though Miiller erroneously 
placed in those genera, together with true “Protozoa,” many 
small worms and wheel-animalcules (Rotifera). He established 
one genus of wheel-animalcules, namely Brachionus, which was 
excellently figured by him and is still recognised by that name, 
though he wrongly included other forms (which his drawings 
show were wheel-animalcules) in his genus Vorticella, together 
with the bell-animalcules clearly recognisable from his drawings. 
He knew and figured the attractive group of Ciliate animalcules 
now called “Hypotricha” with their leg-like locomotive organs 
(Fig. 4). But he classified along with them in his heterogeneous 
assemblage of Infusoria also the minute tailed larve of the para- 
sitic flukes, to which he applied the name Cercaria, still used for 
them. 

O. F. Miller is not only a pioneer in the history of our 
knowledge of microscopic life, and the first naturalist to figure 
accurately and to name the extremely minute organisms which 
are to-day indicated by the comprehensive group-name Bacteria; 
but he has the credit of entering upon the difficult task of naming 
these and the many other kinds of Infusoria revealed to him by 
his microscope in accordance with the binominal method of 
genus and species introduced by Linneus. This is all the more 
noteworthy in that Linneus himself (as pointed out by Miller) 
in his Systema Nature renounced the task, and with what looks 
like a little outburst of temper assigned these minute organisms 
to a debatable group of his great class ““Vermes,” to which he 
gave the name “Chaos’’—chaos infusoriorum, as he writes. 

Miiller made the attempt to reduce this chaos to order, and 
though naturally enough, as a pioneer must, he failed in some 
respects, yet the value of his effort is attested by the fact that 
many of the descriptions given by him are declared to-day to be 
excellent and accurate as far as they go, and many of the names 
given by him in his orderly work are honoured and used by the 
naturalists of to-day. 


874 The Outline of Science 


§ 2 


First Use of the Name Bacteria 

Fifty years after the date of Miller’s work (1786) we find 
another great microscopist—Ehrenberg—completing his cele- 
brated treatise Die Infusionsthierchen als volkommene Organis- 
men (Leipzig, 1838). Ehrenberg (born in 1795, nine years after 
the death of O. F. Miiller) had a much better microscope than 
that of his predecessor, though the instrument was still far from 
the perfection to which it was soon afterwards brought by Amici 
and J. Jackson Lister (the father of Lord Lister the surgeon), 
through discoveries in the “correction” of the lenses combined to 
form the “object glass” or chief element of the system. 

Ehrenberg had been publishing and accumulating his ob- 
servations for twenty years when he produced his magnificent 
folio volumes on “the Infusion-animalcules,” with sixty-four 
plates containing some 1,500 exquisite drawings, many of them 
in colours, all executed by himself and faithfully exhibiting “ani- 
malcules” as shown by his microscope. ‘This treatise is on the 
same lines as, and is an expansion, as it were, of, the work of 
QO. F. Miller, showing an immense progress in half a century, 
both in the capacities of the microscope and the increase in the 
variety and abundance of new kinds of microscopic life now 
distinguished, named, and classified. 

Ehrenberg divided the “Infusoria” or infusory animalcules 
—in which he included all the minute forms of life to be found 
in stagnant pools and puddles, streams and seas, whether fresh 
water or marine—into two classes, “Polygastrica” and “Ro- 
tifera.” The former were distinguished by him from the latter 
as possessing an internal structure consisting of many stomachs 
or digestive sacs, whilst the latter are of larger size and have a 
more elaborated anatomy, together with the remarkable double 
or modified wheel-shaped apparatus beset with vibratile hairs 
(cilia) which Leeuwenhoek had seen for the first time in 1676. 


Bacteria 875 


Ehrenberg gives fine and careful drawings of 169 different 
’ including most, though not all, 
of the more remarkable kinds which we know to-day. They 
form a true and natural group. 


species of “wheel-animalcules,’ 


But his “Polygastrica”’ not only are far remote in structure 
from the Rotifera and far simpler than they are, but are really 
a most variegated assemblage, including, together with many 
kinds of “ciliated’’ animalcules, also whole groups of very simple 
plants—the Diatoms and the Desmids—as well as the animal- 
cules now called “Flagellata,” also the Amoebe (Proteus) and 
the Monads and the Vibrions of O. F. Muller. 

Whilst it is impossible not to admire the patience and skill 
of Ehrenberg in producing his great book, it is the fact that he 
entertained an erroneous theory as to all the lower forms which 
he called “Polygastrica’”—namely, that they possessed numerous 
stomachs and organs of secretion, etc., which he said are visible 
in the larger kinds, but can only be distinguished as minute 
granules in the smallest kinds. This erroneous prepossession 
affected the accuracy of his descriptions and drawings of many 
of his “Polygastrica,’’ which have really no such complete system 
of internal organs, comparable to those of higher animals, as 
he assumed to be the case in his title Die Infusionsthierchen als 
volkommene Organismen. At the same time it is true that the 
larger kinds do show some definite elaboration of internal struc- 
ture. In Ehrenberg’s vague heterogeneous assemblage called 
“Polygastrica,’ many of which, such as the bell-animalcules, 
are beautifully figured by him, we find the genus Vibrio of 
O. F. Miiller—the nearly structureless thread-like species of 
which are amongst the most minute and abundant of “infusory”’ 
organisms—included and raised by Ehrenberg to the dignity 
of a “family,” called by him the “Vibrionia.”’ To it are assigned 
five genera, viz. Bacterium, Vibrio, Spirochete, Spirillum, and 
Spirodiscus. (See Fig. 5 and its explanation.) 

This, then, is the first appearance in scientific literature of 


876 The Outline of Science 


the name Bacrertum, which has persisted and become a general 
name for the immense variety of very simple, very minute, rod- 
like organisms, with which we are in this chapter specially con- 
cerned. It has given origin to the name “bacteriology,” applied 
to the special study of these organisms, which, we now have 
learnt, are immensely important and ubiquitous agents of the 
chemical processes called “fermentation,” “putrefaction,” and 
“disease”! Ehrenberg defined his family “Vibrionia” as “Fili- 
form animals distinctly or apparently ‘polygastric,’ without an 
alimentary canal, naked, legless, with the same structureless body 
as the Monads—forming filiform chains by spontaneous, incom- 
plete, transverse fission.” ‘The genus “Bacterium” he defined 


39 ce 


as “animals of the family Vibrionia assuming by spontaneous 
division the form of a stiff or firm filiform chain.” He recognised 
three species of Bacterium, namely: B. triloculare, B. enchelys, 
and B. punctum. Of the genus Vibrio—differing, according 
to him, but little from “Bactertum” except in flexibility—he 
recognised the species V. tremulus, V. subtilis, V. rugula, V. 
_ prolifer, and V. bacillus. The name “Bacillus” was introduced 
for a species of Vibrio by Q. F. Miller. Like the name “Bac- 
terium,” it has in the course of years gained a wider and more 
general signification, and is to-day often used to include a large 
number of different kinds of rod-like “Vibrions.” Serpentine 
and screw-like forms of these thread-like organisms are placed 
by Ehrenberg in the genera Spirillum and Spirochete. 

We have thus arrived at the period when, through Ehren- 
berg, the minute organisms known to him as Vibrionia (for 
which to-day his generic name “Bacteria” has become universally 
substituted) were definitely set apart as a group. We have yet 
to trace their further study by Cohn, Pasteur, Koch, and a whole 
army of recent investigators, who have shown that these Bacteria 
are really minute plants, allied to the blue-tinted, thread-like 
weeds common in fresh waters, and known as the Oscillatorize 
or Cyanophyce; that they carry on a fundamentally important 


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FIG. 6.—THE VINEGAR FERMENT OR ACETIC 
BACTERIUM (Bacter1um ccett) 


A. The usual filamentous growths, consisting of chains. 
a, long and short constituent rods; 6, shorter rods; c, 
micrococci. B. Distorted growths called ‘‘involution 
forms’’ which occasionally appear in cultures of this and 
other Bacteria. C. Free micrococci. 


D. Free short 
bacilli. Magnified 900 diameters. 


FIG. fipoeY SRICUS FORMS ASSUMED BY THE BACTERIAL 
UNIT OR PLASTID 


a, micrococcus; 6, macrococcus; c, short bacillus; d, long 
bacillus; e, ovoid form or clostridium; f, very large short 
bacillus enclosing sulphur granules (peach-coloured bac- 
terium); g, Leptothrix form; h, vibrio form, slightly undulate; 
i, vibrio form, more undulate; k, spirillum form; 1, folded 
spirillum; m, very short spirillum form; n, close-set spirillum 


form; 0, arborescent form (false-branching) of Cladothrix. 
All except o magnified 1,000 times linear. 


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‘FIG. 8.—GROUPS OF MICROCOCCI MORE OR LESS CLOSELY 
AGGREGATED 


Each micrococcus is about so49, of an inch in diameter. Abundant 
in most putrefactions. (After Cohn.) 


. i 

FIG. 9.—BRANCHING GROWTH OF THE BACTERIUM 

CALLED Cladothrix dichotoma, LIVING IN RIVER 
WATER 


It shows constituent bacillus-like segments and the ‘‘slip- 
ping’’ of these (as at a, b, and c) whilst held together by a deli- 
cate coat of jelly, soas to form false-branching. Magnified 600 
diameters. (After Zopf.) 


Bacteria 877 


activity in relation to the nutrition, indeed the very existence, of 
all living things, being the ubiquitous agents of putrefaction and 
of a variety of chemical changes in living, or recently living, 
matter, leading to the production of a large series of chemical 
substances, many of them important as food to other living 
things; others valued as flavours or for other qualities by man; 
many of them poisonous to him and other organisms, and, in 
fact, the causes of nearly all “infectious” disease. 


§ 3 

Abiogenesis 

Before tracing more of this development of our knowledge 
of, and interest in, the Bacteria, we shall best get a clear notion 
of how it has grown up by calling to mind the influence which 
the discovery of the teeming millions of living things in the 
natural waters of the earth—suddenly revealed by the microscope 
in the years following Leeuwenhoek’s first observations—had 
upon the minds of the more thoughtful and speculative “phil- 


osophers” of those days. 

The immensity of the world of unseen living things sud- 
denly revealed by the microscope was compared by Ehrenberg 
and others before him to the equally astonishing resolution by 
the telescope of the pale cloud of the Milky Way into hundreds 
of thousands of separate stars: a conquest made in the same 
half-century. Unexpectedly life—as to the origin and nature 
of which fanciful guesses and romantic traditions had been 
handed on from remote antiquity—was demonstrated as exist- 
ing in the form of an almost infinite “dust” of invisible particles, 
abounding in all the waters of the earth and dispersed far and 
wide in the dried and pulverised sediment of pools and seas by 
the wind. 


“Spontaneous Generation” 
It was held by an English philosopher, Needham (1750), 
and by others, that this is due to the fact that there is a fertile 


878 The Outline of Science 


or productive “principle” in natural waters which gives rise to 
the Infusoria; whilst others held that water, air, warmth, and 
the remains or débris of animal and vegetable substances are 
necessary for the “generation” of these organisms. These views 
were largely accepted and discussed at the end of the eighteenth 
century as two varieties of the doctrine of “spontaneous genera- 
tion,” or generatio primitiva, or generatio equivoca, as it was 
called. At the present day the term “Abiogenesis” is used for 
the theory according to which living organisms arise from not- 
living matter. It is now held that though in the remote past 
this must have occurred, there is no evidence to show that it takes 
place at the present day. 

In early times Greek, Roman, Hebrew, and Arabic phil- 
osophers accepted the popular beliefs that new generations of 
animals and plants—continually and as a regular every-day 
occurrence—‘‘spring into existence” by the sudden transforma- 
tion of the lifeless decaying substance of dead animals or plants. 
It was also held that often by the sudden “vivification” of the 
inert, mud-like deposits forming the banks of seas and rivers, 
birds and beasts of new kinds are produced, and that the waters 
“bring forth abundantly,” by a normal though mysterious pro- 
cess, fish and creeping things, and sometimes larger beasts. Thus 
there was no difficulty felt in regard to the original creation of 
life on the earth. It was merely an early operation on a large 
scale of the same power which (so it was believed) is at work 
every day in obscure regions of the land-surface undisturbed 
by man’s intrusion. 

The poet Milton set forth in splendid verse this conception 
of the creation of living things. His cotemporary, Sir Thomas 
Browne of Norwich (1670), states his belief in the “spontaneous 
generation” of mice in wheat stores, but is sceptical as to their 
being “bred in putrefaction” in mud or slime, and as to the 
production of the barnacle goose from barnacles, and of these 
from timber. Alexander Ross, a cotemporary, wrote of his 


Bacteria 879 


views: “Sir Thomas Browne may doubt whether, in cheese and 
timber, worms are generated, or if beetles and wasps in cow’s 
dung; or if butterflies, locusts, grasshoppers, shell-fish, snails, 
eels, and such like be procreated of putrefied matter—which is 
apt to receive the form of that creature to which it is by formative 
power disposed. If he doubts of this let him go to Egypt, and 
there he will find the fields swarming with mice begot of the 
mud of Nylus, to the great calamity of the inhabitants.” This 
quotation gives a vivid record of the common opinion of that 
day on Abiogenesis. 

Yet at the very same time Leeuwenhoek was starting the 
investigation of the vast world of “animalcules” by his micro- 
scope, and the Italian Redi made the first step (1668) in the 
scientific refutation of the popular theory of Abiogenesis by 
showing that no maggots were “bred”? in meat on which, by 
means of wire-netting, flies were prevented from laying their 
eggs. It was at this date that the great physician Harvey enun- 
ciated, as a final dismissal of the ancient fancies as to spontane- 
ous generation, the law omne vivwm ex ovo, every living thing 
comes from an egg—that is, from the reproductive form pro- 
duced by a pre-existing living thing. 

During the eighteenth century, as the result of Redi’s 
experiment and similar observations of a very simple kind, the 
general belief in Abiogenesis or spontaneous generation, in so 
far as the larger forms of life are concerned, disappeared. 

But it found a new scope when the existence of a world 
of well-nigh invisible organisms was made known at this critical 
moment by the microscope. We have seen that Needham and 
others indulged in large speculations based on the supposed 
spontaneous generation of the swarming dust of animalcules 
now discovered. “True!” they said, “the larger forms of life 
are only produced by parentage; but this newly-discovered world 
of minute creatures arises by Abiogenesis, and in due course they 
gave birth to larger organisms.” It was an Italian, Spallanzani, 


880 The Outline of Science 


who applied to the problem thus restated the same kind of test 
as that used a hundred years earlier by his compatriot Redi. 
He demonstrated that if a natural water or an infusion teeming 
with microscopic animalcules were heated to boiling-point, the 
animalcules were killed, and if the flask in which the liquid was 
contained was now hermetically closed, the liquid became clear, 
and no living things could be found in it, even after it had been 
thus kept for many weeks. But when the flask was opened and 
the liquid in it exposed to the inflow of air, then, after a few 
hours, infusorial animalcules were again found living in thou- 
sands in it. Spallanzani drew the conclusion that the “eggs’’ or 
“germs” of the animalcules were carried in the dust of the air 
and so gained admission to the liquid when the flask was opened. 


§ 4 


A Long Controversy 
A controversy thus arose which has continued into our own 
times, and has led to very important knowledge as to the con- 


4 


ditions necessary for the life of the “infusory animalcules” and 
also as to the many different kinds included under that name, 
as well as to the means of keeping liquids containing organic 
matters (such as infusions or solid vegetable and animal sub- 
stances) altogether protected from the access of “infusory ani- 
malcules.” Liquids so treated are said to be “sterilised.” In 
order to study the question as to the existence of Infusoria or 
their reproductive germs as dust in the air, it was necessary to 
“sterilise’” an infusion, such as that of hay or roots, fruits or 
flesh, which was to be used (like the raw meat in Redi’s experi- 
ment) to feed or cultivate the air-carried germs should they gain 
access. ‘lhe experimenter had to begin by preparing an unin- 
fected “culture-fluid” which, though free from living Infusoria, 
should yet be capable of affording them nourishment should they 
gain access to it. 


Bacteria 881 


It was agreed, as Spallanzani had declared, that by heating 
an infusion of any kind to the temperature of boiling water and 
keeping it at that temperature for five minutes all animalcules 
or their germs already living in the infusion could be (with rare 
exceptions) killed. The exceptions were, it was found at a later 
date by Ferdinand Cohn (1870), due to the existence in some 
eases of a hard dried condition of those animalcules called 
Bacteria, or their reproductive spores. ‘These resisting “spores” 
were destroyed either by an exposure of three hours to the boil- 
ing temperature or by soaking in warm water for some hours 
before the exposure to the temperature of boiling water. 

Spallanzani’s conclusion that the appearance of animalcules 
in such boiled infusions could only be accounted for by the access 
of air-carried germs to the infusion after it had been boiled was 
met by his opponents with another suggestion. ‘They suggested 
that the Abiogenesis or spontaneous generation of animalcules 
depended on a special chemically active condition of the air 
present in the flasks, which when closed were filled half with 
liquid and half with atmospheric air. It was supposed that the 
heating of this air to a high temperature and its consequent rare- 
faction before the closure of the flask did not act merely by 
destroying germs floating in it but destroyed its power of 
chemical action on the organic infusion. But it was not shown 
by any well-devised experiment that air when freed of organic 
germs before admission to the sterilised fluid in the flask by 
filtration through cotton-wool, possessed nevertheless this vivify- 
ing quality. And it was shown that the admission of unfiltered 
air to the flask resulted in the production of animalcules in the 
infusion. ‘This fact was in accordance with the supposition of 
Spallanzani, that the unfiltered air brought with it, in the form 
of dust, the actual living though incompletely desiccated animal- 
cules or their reproductive germs. These were excluded when 
filtration was used, just as Redi’s blow-flies were excluded from 
access to the meat which he placed under covers of wire-netting. 


VOL. IV—2 


882 The Outline of Science 


In the early years of the nineteenth century the controversy 
of opinion concerning “‘spontaneous generation” continued with- 
out any experimental decision, until in 1837 Theodore Schwann 
—who was the author of the cell-theory of organic structure and 
function, also the discoverer of “‘pepsin,” the digestive ferment 
of the stomach, and the first to apply the experimental methods 
of the physicist to the investigation of the animal machine—made 
some well-contrived decisive experiments, confirmatory of Spal- 
lanzani’s conclusion. Schwann boiled his experimental fusion 
in a flask with a long tube-like horizontal neck. He did not 
close the neck, but kept it heated by a flame so that no living 
particle could pass and enter the flask when air was drawn in 
by the cooling of the flask. The infusion in the flask remained 
sterile for many weeks—in fact, so long as the neck was kept 
nearly red-hot by the flame. But when the flame was removed 
and unheated air allowed to enter the flask the infusion became 
turbid and swarmed with Infusoria, since their germs were no 
longer destroyed on their way inward through the heated portion 
of the neck. 

Schwann completed his experimental inquiry by demon- 
strating by chemical analysis that the atmospheric air, after 
passing the heated neck of the flask, contained as much free 
oxygen gas as does normal atmospheric air, and that it was capa- 
ble of supplying the respiratory needs of frogs which (he found) 
lived healthily in a chamber supplied only with such air. The 
air was cooled and conducted into this chamber after passing 
the heated region. 

By this date (as we have seen) the knowledge of the shape 
and character of the various kinds of Infusoria when studied 
with the microscope had become greatly increased owing to 
Khrenberg and other writers. It is therefore surprising that 
Schwann writes of the organisms which appeared in his infusions 
or were successfully kept out of them simply as “Infusoria.” 
He gives no description of these Infusoria, but draws a sharp 


saao 


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, 4 
tame 
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2 8 
esl aet 
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eer 


From Zopf, Die Spaltpilze, Breslau, 1885. 


FIG. 10.—VARIOUS GROWTH-FORMS OF Cladothrix dichotoma 
OF ZOPF—A ‘‘PLEOMORPHIC’’ OR ‘‘MANY  SHAPED”’ 
BACTERIUM 


A. Branching plant, the branches tending to be vibrio-like (a) 
and spirillum-like (b). B. A branch showing both forms of growth. 
C. Very long, closely twisted, spirillar branch. D. A branch de- 
taching a free spirillum. E. Branches: a, unsegmented; b, divided 
into rod-like segments; c, divided into micrococcus segments. F. 
Spirillum-like branch: a, undivided; b, divided into long rods; c. 
short rods; d, micrococci. 


FIG. 10 bts.—PART OF AN 
ARBORESCENT JELLY-MASS 
OR CQENOGL2ZA, FORMED BY 
Cladothrix dichotoma 
(See Fig. 21, F.) 


Enclosing division-products otf 
various shapes and sizes. a, 
short rods; 6, long rods; c, 
Leptothrix or filamentous forms; 
d, vibrions; e, spirilla. (After 

Zopf.) 


2 


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FIG. I1.—PLEOMORPHISM OR VARIETY OF GROWTH-FORMS 
SHOWN BY THE Bacterium merismtpedtotdes 


Described by Zopf from freshwater, putrid pond-slime at Berlin. 
I, unsegmented filament; 2, long segments (bacilli); 3, short rods 
(such as used to be distinguished as ‘‘ bacteria,’’ but can no longer 
be so named since that word applies to the whole class or group of 
“‘Schizomycetes’’; 4, cocci or spherical segments; 5, all three forms 
of segment in one filament. A, B, C, filaments dividing into cocci; 
I, isolated cocci; D-H, successive phases in the formation by 
budding of ‘‘tablet-colony’’; J, a moderate-sized tablet-colony 
consisting of thirty-two tetrads (groups of four cocci). Compare 
this with Fig. 17. 


Bacteria 883 


line between them and the “moulds” (minute branching, thread- 
like organisms classed with the Fungi), the spores or germs of 
which are, he says, liable to appear in infusions exposed to con- 
tamination by atmospheric dust. He makes some important 
observations on what he calls “the well-known granules” of 
which beer-yeast consists (discovered by Leeuwenhoek one hund- 
red and fifty years earlier). He shows that they are living 
vegetable organisms, and describes their growth and multiplica- 
tion by budding. 

The important feature in this contribution to the subject 
by Schwann is that he ascribes the putrefaction of the infusions 
in which “Infusoria” appear to the life and nutritional processes 
of the Infusoria. He says they take chemical elements from 
the infusion of vegetable matter as nutrition, and this causes the 
breaking down or putrefaction of the organic chemical compound 
which is dissolved in the infusion. Thus, according to him, putre- 
faction is the immediate outcome of life and not of death, for 
without the presence of the living Infusoria the infusion would 
remain clear and unchanged for an unlimited period. And he 
argues that the conversion of sugar into alcohol by yeast is due 
in a similar manner to the life and growth of the beer-yeast 
organism, which takes the elements which it requires from 
the sugar, so that the chemical combination known as sugar 
is broken down and the residue forms into alcohol and car- 
bonic acid gas. ‘Thus Schwann for the first time formulated 
the doctrine that fermentation is due to the action of living or- 
ganisms, and asserted the general similarity of “putrefaction” 


39 


to alcoholic “fermentation,” the former caused by unnamed 
“Infusoria,” the latter by the beer-yeast. This was the very 
reverse of the then largely prevalent chemical doctrine that 
putrefaction was set up by the action of atmospheric oxy- 
gen, which, it was supposed, gave rise to the Infusoria ac- 
companying putrescence, by “Abiogenesis” or spontaneous 
generation. 


984 The Outline of Science 


, Closer Study of Infusions 

After Schwann had briefly attributed the production of 
putrefaction to what he called, without discrimination, “Infu- 
soria,”’ the careful study of the Infusoria concerned in that pro- 
cess by means of the improved microscopes of the period 1840- 
60 was obviously the next step which had to be taken. It was 
gradually effected. Leeuwenhoek and all the describers of “In- 
fusoria”—including Ehrenberg—had, in searching for these 
microscopic forms of life, examined both (a) natural “infusions,” 
such as the waters and slime of ditches, pools, and ponds, and 
also (b) artificially prepared infusions obtained by letting dead 
leaves or hay or dead animal matter soak in jars or dishes con- 
taining water. The rich population of bell-animalcules, of rela- 
tively large Ciliates, swimming and creeping forms, and of 
Rotifers or wheel-animalcules was obtained from the naturally 
accumulated infusions of long standing—in ancient ditches and 
pools, and to some extent also in the artificial infusions kept in 
vessels for many weeks under frequent examination by the 
microscopist. 

But when the occurrence of the spontaneous generation of 
“Infusoria’” was in question artificial infusions were employed, 
which were first purified or freed from all life by heat. Then 
being freely exposed to contamination by atmospheric dust or 
contact with unsterilised objects, such as a glass rod or a man’s 
finger, they became in the course of a few hours charged with a 
living multiplying cloud of the minutest organisms, and in a 
day or two were putrid and foul-smelling. It was observed and 
fully established that the larger “Infusoria” do not appear at 
once in these rapidly formed growths, and have no part in causing 
putrefaction. ‘These growths consist exclusively of the peculiar 
excessively minute rods and threads and spherical forms called 
Vibrionia and Monadina by Ehrenberg (our Bacteria). 

It is not until a later stage of the putrescence of a freshly- 
made infusion—attained after a period varying from a few days 


Bacteria 885 


to a month—that the larger “Infusoria” make their appearance. 
Their germs (spores, eggs, or their desiccated bodies) are not 
nearly so abundant and ubiquitous as those of “Vibrionia” (Bac- 
teria). They cannot flourish in an infusion until the Bacteria 
have established themselves and are ready, like the grass-crop in 
a grazier’s paddock, to serve as the food of the larger forms. 
Until the interest in the question of spontaneous generation be- 
came very pressing, no one had supposed that the various kinds 
of microscopic organisms arbitrarily assigned to a group as 
“Infusoria” (a “chaos” as Linneus called it) made their appear- 
ance in an infusion successively as separate stages of its history, 
and that the earliest to appear differ from the later in the same 
ways as plants or vegetables differ from animals. 


The Bacteria Removed to the Vegetable Kingdom 

It is not possible to give the credit for this observation to 
any one individual. But the botanists who occupy themselves 
with the study and systematic classification of Alge and Fungi, 
especially with the microscopic forms of filamentous water- 
weeds and of mildews and moulds, about the years 1840 to 1860, 
with the general assent of biologists removed the Vibrionia, the 
Desmids, and the Diatomacee from Ehrenberg’s “Infusoria”’ 
altogether and definitely assigned them to the Vegetable 
Kingdom. 

Rabenhorst, Kutzing, and Nageli were the chief amongst 
these botanists, who, as a consequence of their very extensive 
study of the lowest microscopic plants, broke up and rearranged 
the old “chaotic” group called Infusoria. The most striking fact 
which they established was that the organisms which cause putre- 
faction, the Vibrionia or Bacteria, are not “‘animalcules”’ at all 
—are not, in fact, animal in nature or nutrition as previously 
assumed, but are plants allied to the delicate water-weeds known 
as “Oscillatorie.” At the same time zoologists agreed that the 
Rotifera cannot be associated on structural grounds with the 


886 The Outline of Science 


other animalcules classed by Ehrenberg and Miiller as Infusoria, 
but must be classed with the higher group of Annulose animals. 
In fact, as a result of mere revision the class “Infusoria,” so 
named by O. F. Miiller and adopted by Ehrenberg, fell to 
pieces, resolving itself, when the botanists had taken the Bac- 
teria, the Desmids, and the Diatoms, and the zoologists had 
removed the wheel-animalcules, into a natural assemblage of 
microscopic wnicellular animals, to which, about 1860, von Sie- 
bold gave the name “Protozoa.” 


Pasteur’s Early Discoveries 

Whilst the new conception of the nature and activity of 
the Vibrionia was developing, and their many points of resem- 
blance to the delicate thread-like Oscillatoriz were being demon- 
strated, an epoch-making impulse was given to their investigation 
as agents of fermentation by the discoveries of the great French 
chemist Louis Pasteur and the theoretical views which he estab- 
lished. Pasteur found that the ammoniacal decomposition of 
urine is due to the growth of it in swarms of a special, very 
simple kind of Vibrion or Bacterium, and further that the change 
of wine and beer into vinegar is due to special kinds of acetifying 
bacterial ferments which multiply in it by the million (see Fig. 6). 

The first discovery of a disease-producing Bacterium was 
made by the French pathologist Davaine in 1854. He found 
that the blood of sheep suffering from the disease known as 
splenic fever or anthrax (to which men and other animals are 
also liable) is occupied by countless swarms of a rod-like bac- 
terial parasite, and concluded that they were the active cause of 
the disease (see Fig. 23). Later (1863) Pasteur investigated 
this disease and proceeded to discover and study other “bac- 
terial” diseases (e.g. fowl cholera, silkworm disease or “pebrin,” 
etc.). Pasteur’s investigations were always directed to the con- 
trol of the diseases studied by him and their ultimate banishment 
from the life of man and his domestic animals, or on the other 


Bacteria 887 


hand to the control and improvement of process such as brewing 
and the making of wine and of vinegar, in which living ferments, 
Bacteria and yeasts, play an important part either helpful or 
injurious to man’s enterprise. 


The Steps Leading to our Present Knowledge of the Bacteria 

We have now followed in outline the steps by which our 
knowledge of the Bacteria entered upon its present vast practical 
and theoretical importance. These steps are indicated by the 
following epitome: (1) invention and early use of the micro- 
scope; (2) theory of spontaneous generation or abiogenesis; 
(3) discovery of the vast world of microscopic Infusoria or In- 
fusion-animalcules; (4) first use of the name “Bacteria”; (5) 
experimental rejection of the theory of abiogenesis and discovery 
that the Bacteria are the living agents of putrefaction; (6) and 
of many other fermentations; (7) and that many deadly diseases 
of men and animals are “fermentations” caused by intrusive 
Bacteria; (8) that Bacteria agree with certain Alge or aquatic 
plants (the Oscillatorie or Cyanophyce) in structure and 
growth and nutrition, and must not be classed as animals. 

We shall now, as briefly as the purpose of this “outline” 
necessitates, give some account of the present state of our know- 
ledge of the Bacteria. This knowledge has grown during the 
last sixty years from the beginnings above sketched to an almost 
incredible extent—spreading out into a number of very distinct 
branches, pursued in great laboratories by thousands of eager, 
specially trained investigators, led by the ablest chemists, physi- 
ologists, hygienists, and pathologists of our time. It has received 
on account of the importance and novelty which characterise it 
a special title as a branch of science, viz. Bacteriology. 


§ 5 
Forms of Bacteria 


The Bacteria are now recognised as a group or class of 
very minute rod-like, spherical, or filamentous aquatic plants. 


888 The Outline of Science 


They are allied to the common blue-green water-plants or Alge 
known as the Oscillatoria or Cyanophyce—in their simplicity 
of structure and form, in much of their physiology and life-his- 
tory, and also in the fact that they multiply by transverse fission 
—whence both are called Schizophyta (splitting plants). They 
are remarkable for their varied chemical activities, including the 
production of many kinds of “fermentation,” but do not agree 
in structure and life-history with the yeasts and moulds, the 
agents of the fermentations in which alcohols are produced from 
various kinds of sugar. 

The name Bacteria has reference to the fact that they most 
commonly occur as swarms of many millions of minute separate 
rods. Usually, each rod is only 1/50,000 in. (or half a micron) 
in width and 1/25,000 (or one micron) in length (see Fig. 11). 
But often the swarms consist of individuals all uniformly seven 
or eight times longer and a little broader than this. Swarms 
consisting of individuals uniformly of smaller size than this are 
frequent. ‘These rod-like units, whether short or long, are now 
ealled bacilli (Fig. 7, c to f), the name “bacterium,”’ which was 
at one time used to distinguish the shorter rods, having become 
generally applied as a name for the whole group. Instead of 
dividing into two after moderate growth in length, the bacilli of 
some kinds, under conditions not precisely determined, grow 
greatly in length so as to form delicate straight filaments, which 
are called “Leptothrix forms” (Fig. 7, g) in allusion to an 
Oscillatorian of that name. Further, such elongated growths 
may be not straight but slightly serpentiform, when they are 
called “Vibrio forms” (Fig. 7, h-i). The name Vibrio is that 
originally given to the whole group of Bacteria by O. F. Miiller, 
but has been now restricted to these undulated forms. The same 
process of growth or twist carried further gives us screw-like 
filaments which may be more or less open or else closely turned 
spirals; these are called “spirillum forms” (Fig. 7, k to n). 
These filamentar growths, whether straight or spiral, often show 


| A | FIG. I3.—LIVING SPIRILLA FROM A DROP OF SEWAGE- 
—: TIN IIs F TYPHOID FEVER J 
FIG. 12.—THE LIVING BACILLUS O WATER 
i life taken with dark-ground ; 
An ST hi a amin (Pathé fréres Paris) An instantaneous photograph from life with dark-ground illumina- 
iilumination by : F : 


tion, taken by Dr. Commandant, of Paris. 


° 
x 
a 


Soo me9 lO 20, 


1 IP ry 0 
LY, Mena, 
¢) Be, OG gis 0 


tg) 
Ys 
; 
2 


ASS y 


FIG. I4.—THE “HAY-BACILLUS,”’ Bacallus 
subtilis, OF COHN AND SUBSEQUENT 
WRITERS 


A. Free-swimming bacilli, showing a cilium 
at each end (but see A in Fig. 15). B. Filament, 
or Leptothrix form dividing into bacilli. C. 
Similar filament with shorter segments. D. 
Filament in which the segments (bacilli) have 
formed statospores. EF. Spores with swollen 
jelly-like envelope. fF. Liberated spores: a, 
before, b, c, d, during germination. Note the 
non-polar lateral position of the new growth 
or sprout. (Compare with Figs. 23 and 24.) 
G. Membrane-like jelly enclosing rows of the 
hay-bacillus. 


FIG. I5.—DEEPLY STAINED PREPARATIONS MADE IN 

ORDER TO SHOW THE VARIOUS FORMS OF CILIA AND 

THEIR ARRANGEMENT IN DIFFERENT KINDS OF 
BACTERIA 


A. Bacillus subtilis. B. Micrococci with single cilium. Cand 
D. Larger oval plastids with single cilium from green pus. E. 
A larger kind of colour-producing bacterium, with a bunch of cilia 
at one pole. F. Bacillus of typhoid fever, showing many 
scattered cilia, not visible during life (see Fig. 12). G. A large 
bacillus with numerous cilia all over its surface. H. The comma 
bacillus of cholera described by Koch (see Fig. 31). J, K, L,M. 
Spirilla of various origin, showing polar cilia. 


Bacteria 889 


a jointing or structural division into segments corresponding to 
long or short bacilli, and they may eventually break up into 
separate pieces of that nature (see Figs. 9, 10, 11,14). In some 
of the spirillum forms such a breaking up results in their separa- 
tion into curved, “comma’’-like segments. This is the case with 
the spirillum, which is the cause of cholera and led its discoverer, 
Koch of Berlin, to call it “the comma-bacillus” (Fig. 29). 
Bacilli, vibriones, and spirilla may, but do not necessarily 
always, break up by transverse fission and contraction of their 
substance into spherical units, which are called “micrococci,” or 
“coccus forms” (Fig. 7, a). Micrococci multiply rapidly by 
transverse fission and form immense growths consisting of this 
form only (Fig. 8). The conditions which determine the forma- 
tion of micrococci by fission of bacilli or of the filamentar Bac- 
teria are not determined. Probably very many micrococci have 
become fixed or limited to the production of this form, and whilst 
they themselves are not constantly or regularly produced from 
elongate forms they have lost the power of elongating so as to 
produce bacilli or filaments. They and probably many bacillar 
forms have all been derived from ancestral stocks which showed, 
as do some of their progeny, a certain freedom of growth rang- 
ing from micrococcus to leptothrix and spirillum forms (see 
Figs. 9 and 10). But just as the simple pullulating yeasts called 
Saccharomyces are to be regarded as a specialised arrested race 
budded from the submerged branching threads of a mould of 
elaborate structure, and can no longer (so far as experimental 
research shows) grow into the larger form from which they took 
their rise, so many micrococci and bacilli have lost the capacity 
for filamentar growth and are restricted to the form of a minute 
sphere or a short rodlet. Nevertheless, many of the Bacteria do 
show these and other variations in their growth; especially do 
those which live in open streams and ponds and have not lost 
their capacity for varied growth by adaptation to special con- 
ditions, such as those of parasitism. It is a matter of extreme 


890 The Outline of Science 


difficulty to isolate and to cultivate in a variety of conditions a 
particular Bacterium so as to be able to say with certainty, as 
a result of direct observation, “this form gives rise by growth to 
that form.” In a few cases it has been done (see Figs. 6, 10, 
and 11). It is even more difficult to prove a negative and to 
show that wnder no possible change of conditions does this form 
grow into that form. Some writers (e.g. Winogradski), having 
kept a given form of bacterium under observation with the micro- 
scope for some weeks during which it grew and multiplied with- 
out change of form, have unreasonably put forward the 
conclusion that such change of form never occurs, either in this 
or any other bacterium, even when exposed to new conditions 
of nourishment and environment not tested by them. 

Strangely swollen and distorted enlarged Bacteria are occa- 
sionally produced in unusual chemical conditions of cultivation, 
and are called “involution forms” (see Fig. 6). 


Multiplication and Movements 

The rate of growth and multiplication of micrococci and 
bacilli is a very high one. A common bacillus (Fig. 14), known 
as “the hay bacillus” because it occurs in infusions of hay, has 
been observed to double in length and to divide every half-hour. 
One such bacillus would thus under favourable circumstances 
produce 1,024 bacilli in five hours, over a million in ten hours, 
and some millions of millions in twenty-four hours! 

Bacilli, micrococci, and spirillum forms of Bacteria are fre- 
quently found actively moving and darting through the liquid 
in which they form a dense swimming cloud (so-called “swarm- 
ing phase’). They also often abandon this movement and settle 
down as motionless particles (“resting phase”). Their locomo- 
tion is due to the presence on their surface of extremely delicate 
threads of protoplasm, which keep up a lashing movement. 
Such are commonly seen on the bodies of aquatic animalcules, 
and on the structural units or cells of the moist surfaces of higher 


Bacteria 891 


animals, and are called “cilia” (Fig. 3). The Bacteria shed their 
cilia when they enter upon a resting or motionless period of life. 
It is only in recent years, by the use of skillfully applied stain- 
ing liquids and the highest powers of the microscope, that the 
cilia of the Bacteria have become, step by step, clearly known. 
They are so delicate, transparent, and minute as to be invisible 
unless artificially stained. They are figured as seen when 
strongly stained—in preparations of different kinds of Bacteria 
—in Fig. 15. They may be single, few, or numerous, and may 
exist at one or both ends of the Bacterium, or all about it. The 
ciliary locomotion of the Bacteria is easily distinguished from 
the tremulous “Brownian” movement which, like other minute 
particles suspended in liquid (e.g. gamboge resin), they some- 
times exhibit. 


The Jelly Phase 

A general feature of the life and growth of Bacteria of a 
varying character is the production of a film of jelly on the 
surface of each little individual. This jelly may be the thinnest 
film, and act so as to keep the products of fission in conjunction 
with one another (Figs. 16 and 17). This is particularly im- 
portant in the form known as Cladothrix (Fig. 9), where a kind 
of false-branching results from the side-slipping of the terminal 
part of a filament, the broken-off part being retained in position 
by the delicate gelatinous coat. ‘True branching does not occur 
in the Bacteria. Again, the jelly may form a thick transparent 
coat (Fig. 18), or the jelly of neighbouring units may be very 
abundant and fuse into a common Jelly in which the jelly-form- 
ing Bacteria are embedded (Fig. 19). In that case the jelly 
may be some inches in area (Fig. 20), and even fill, as a trans- 
parent coherent mass, a glass jar in which the Bacteria are grow- 
ing. The term “zoogloea” is applied to these copious productions 
of jelly, and botanists speak of the “zoogloea-phase” of the Bac- 
teria. The term “zoogloea” is objectionable because it implies 


892 The Outline of Science 


that the jelly is of animal origin, which it is not. “Glceogenous” 
is the most suitable term to apply to Bacteria which are in this 
phase of growth, and the jelly itself should be called the “cceno- 
gloea” or “common jelly” of this or that kind of Bacteria. 
Very many different kinds of Bacteria—but by no means 
all—at one time or other in their growth produce a more or less 
abundant “common Jelly” or “coenogloea.” Remarkable varieties 
of shape and density are produced in different cases (Fig. 21). 
A common form is that of a resisting membrane or skin which 
forms on the top of the liquid in which the Bacteria are living, 
or on a submerged surface—this is called a “mycoderma” (Fig. 
21, 4). Ball-like, branching, and net-like forms of the coeno- 
gloea are known (Fig. 21, C). Often Bacteria of different kinds 
and chemical property become embedded in one common 
jelly and form a residential colony of reciprocally helpful kinds 
of Bacteria. The ginger-beer plant, which includes yeast cells 
in its association, is an example (Fig. 22), so are the “mother 
of vinegar’ and the koumiss ferment. They are symbiotic 
growths, similar to the lichens in their composite character. 


Reproduction of Bacteria 


No process corresponding to conjugation has been observed 
in Bacteria nor has the production of male and female spores. — 
Though all reproduce by the simple separation of the products of 
fission which resemble one another, yet in a large number of 
kinds of Bacteria the formation of reproductive spores of an 
enduring character called “stato-spores” has been observed. 
Under given conditions of nutrition, not precisely determined, 
the protoplasm within a bacillus or in a joint or segment of a — 
filamentous “leptothrix-form” or spirillum-form contracts so as 
to form an oval, dense, highly-refracting body which acquires its 
own special “coat.” 'These “spores” have the power of resisting 
desiccation and high temperature to a greater extent than can the 
unchanged substance of a bacillus or bacillus-like segment. They 


Bacteria 893 


are “resisting spores” or “stato-spores.”. Some of these are 
represented in Figs. 14, 24, and 25. It is not possible to divide 
the Bacteria into the “spore-producing” and the “non-spore-pro- 
ducing”’ (as has been proposed), because we do not know enough 
about the forms which are not known to produce spores to be 
sure that they never do! The hay-bacillus and the bacillus which 
produces the disease known as “anthrax” or “splenic fever’’ are 
good examples of spore-producing Bacteria, and are very much 
alike (Figs. 14 and 23). They both, in certain conditions, grow 
into long filaments (leptothrix-form) in which stato-spores are 
formed in a row (see Figs. 14 and 24). It was thought (by 
Buchner) possible that the anthrax bacillus is only a hay-bacillus 
modified by parasitism in the blood. But a decisive difference 
was discovered when the germinating spores were observed with 
the highest powers of the microscope. The new young anthrax 
bacillus (Fig. 24) sprouts from one end or pole of the oval 
spore, whilst the hay-bacillus arises from the mid-region of the 
oval spore (Fig. 14, #'). Some writers apply the term spore to 
the swimming free bacilli and micrococci produced by the simple 
fission of leptothrix-forms or of long bacilli. But this is a misuse 
of the term spore, which should refer to a bud or seed-like 
particle specially modified so as to ensure its locomotion or else 
resistance to destructive agencies and its growth into a new 
individual, and not to the ordinary abundant fission-products of 
vegetative life. 


§ 6 


Protoplasm of Bacteria 

The structure of the protoplasm of which the Bacteria, 
whether cocci, bacilli, or filaments, consist is extremely difficult 
to determine on account of their minute size. By analogy with 
other simple organisms (such as the yeast cell), we should ex- 
pect to find that each of the segments of a filamentous bacterium 


894 The Outline of Science 


(and every detached segment called “coccus” or “bacillus”) has 
the structure of a typical cell; that is to say, has a “nucleus” or 
denser central body of a certain definite structure, consisting 
largely of granules or threads of a readily-stained substance 
called “chromatin.” In typical “cells” (Figs. 2 and 3) the 
nucleus is surrounded by less dense protoplasm, in which are 
various granules and vacuoles, or liquid-holding cavities. But 
it appears from long-continued inquiries into this matter that, 
contrary to what we find in typical “cells,” the Bacteria have not 
a true nucleus, though many have chromatin granules, and in a 
few a deeply placed stain-taking body has been observed. The 
outer region of the Bacterial “plastid” or unit is denser than 
the deeper part. Granules of chromatin and of other chemical 
nature, and in one kind (the so-called sulphur-bacteria) granules 
of sulphur, are scattered in the outer substance (Fig. 7, f). The 
structural units of some of the Oscillatorie (allied to the 
Bacteria) are apparently also devoid of a nucleus, though in 
others an irregular stainable body, which probably represents the 
nucleus of a typical cell, is present. The structure of the 
bacterial plastid throws little, if any, light on the very elaborate 
chemical processes in which it is the active agent; nor on the 
growth and the shedding of its locomotive cilia. 

We have so far summarised what is known as to the form 
and structure of Bacteria. Their relations to surrounding physi- 
cal conditions, and to the chemical nature of the organic infusions 
in which they flourish, require a brief statement. 

The chemical problems involved cannot be discussed without 
dealing with some of the most novel and difficult questions of 
Organic Chemistry, which lie far beyond the scope of this 
chapter. 


Influence of Moisture Desiccation 
Bacteria, like all living things, owe their distinction from 
“dead” or “non-living matter” to the presence in them, as a main 


FIG. 16.—MESHWORK LIKE THAT OF THE 
GREEN FRESHWATER ALGA HYDRO- 
DICTYON 


Formed by bacilli of the pleomorphic peach- 
coloured Bacterium (B. rubescens). From 
Lankester, ‘‘On a Peach-coloured Bacterium ”’ 
(Quart. Journ. Microsc. Sci., vols. xiii. and 
XVie}e 


FIG. I17.—THE BISCUIT-SHAPE OR 
FIGURE-OF-EIGHT PRODUCED BY D H 
AN INCOMPLETE DIVISION OF A _Seecccee) 

SPHERICAL OR COCCUS FORM Se 


FIG. 18.—THE PATHOGENOUS 
BACTERIUM WHICH CAUSES 
PNEUMONIA. (FROM THE 


This was at one time regarded as the 
typical form of ‘‘Bacterium’’ when 
that word was used by Cohn as the 


name of a genus. The figure shows 
eight of such units or “plastids” 
adherent to one another in regular 
tablet form (from a growth of the 
peach-coloured Bacterium, B. rube- 
scens). Original. 


LUNG OF A MOUSE) 


The thick envelope or coat of a 
jelly-like character is remarkable. 
Both elongate (bacillar) and 
spherical forms areshown. Magni- 
fied 1,000 times linear. 


FIG. 19.—Leuconostoc mesenteroides (Cienkowski)— 

THE ‘‘FROG’S SPAWN’’ GROWTH—A GLCZOGENOUS 

BACTERIUM WHICH OCCURS IN THE VESSELS IN WHICH 
BEET-SUGAR IS BEING EXTRACTED FROM ROOTS 


It develops from minute spherical spores (1) which form a 
jelly-like coat around themselves (2, 3) and divide to form a 
row of micrococci (4, 5, 6). Large accumulations of the jelly- 
masses (7, 8) are thus produced and cause a ‘‘ropy”’ condition 
of the sugar. In 9 two chains of the micrococci are seen with 
single larger cocci interspersed. Compare with the allied but 
much larger organisms Nostoc and Anabena, belonging to the 
group Cyanophyce. 


FIG. 20.—ZOOGL@A OR CCZNOGL@A, OR JELLY-MASS 
FORMED BY A BACTERIUM GROWING ON A SLICE OF 
CABBAGE ROOT 


Drawn of the natural size. The bacteria enclosed are grouped 
in chains which resemble those of Anabena and Nostoc. 


Bacteria 895 


part of their substance, of peculiar compounds of the elements 
Carbon, Hydrogen, Nitrogen, and Oxygen, with some Sulphur 
and minute quantities of phosphates, lime, and alkalis. These 
compounds are combined to form a viscid labile material which is 
called “protoplasm” or “cell-substance.” ‘To be permeated by 
water—that is, moisture in greater or less quantity—is essential 
for the active life of protoplasm; but it can survive desiccation— 
in some instances—in a quiescent state described by the term 
“suspended animation” (as in the case of the wheel-animalcules 
and Tardigrades). Thus we find that the Bacteria are active 
growing, multiplying, and moving—when in damp surroundings 
or actually submerged, and that although many of the more 
delicate kinds are killed by drought others survive desiccation, the 
formation of hard-shelled resisting “spores” (or stato-spores) 
aiding that survival. 


Influence of Heat and Cold 

Many kinds of Bacteria flourish in sea-water at 0° C. It 
has been found that a very low degree of temperature (e.g. that 
of liquid hydrogen — 252° C.), whilst suspending their activities 
leaves them uninjured. On the other hand, most Bacteria are 
killed when the temperature is raised to about 55° C. Some 
live in hot-springs and can flourish at 72° C. All non-spore- 
producing Bacteria are killed almost instantaneously when 
placed in boiling water (100° C.). But the spores of some of the 
spore-producing kinds are capable, if old and dry, of resisting 
exposure to boiling water for three hours, younger spores in a 
moist condition are more easily killed. These facts as to resist- 
ance to heat have especial importance in reference to the prepara- 
tion of sterile infusions and jellies (that is, pure and free from 
germs) to be used in the cultivation and separation of different 
kinds of Bacteria in the laboratory. They are, in fact, the 
foundation of the science of bacteriology, and also of the suc- 
cessful carrying on of the great commercial enterprises of can- 


$96 The Outline of Science 


ning fruit, vegetables, fish, and flesh for use as human food. 
They are and have been of no less critical importance in the 
examination of the, now discarded, belief in spontaneous genera- 
tion (see above). The great poet-philosopher Goethe knew the 
facts demonstrated by his cotemporary Spallanzani, and also had 
seen the swarming animalcules revealed by the microscope. 
We find accordingly that, in a discussion with Faust, Goethe 
makes Mephistopheles protest in words which are precisely in 
accordance with modern knowledge of bacteriology: 

In water, in the earth, in air, 

In wet, dry, warm, cold, everywhere, 

Germs without number are unfurled. 

And but for fire and fire alone 


There would be nothing in the world, 
That I could truly call my own. 


The translation is Sir Theodore Martin’s. 


Influence of Light 

It has now been definitely demonstrated that direct sunlight 
has a destructive effect on many kinds of Bacteria. ‘The violet 
rays are the most deadly. Water exposed in open reservoirs and 
shallow lakes and streams to the sunlight is freed to a large extent 
of such disease-producing Bacteria as those causing typhoid, 
anthrax or splenic fever, and others which are specially liable to 
destruction by the sun’s rays. It was found by Dewar that a 
liquid containing the Bacteria which cause phosphorescence of 
butchers’ meat and dead fish can be frozen at the temperature of 
liquid air, and kept solid for some months without injury to the 
Bacteria if not exposed to daylight. The Bacteria became active 
and phosphorescent when the liquid containing them was sub- 
sequently thawed. No chemical or mechanical agency could in- 
jure them when in this hard-frozen condition, yet they were not 
inaccessible when in this state to the destructive action of the 
violet rays of sunshine. Though frozen solid and unassailable by 
all other agencies, it was discovered that light rays could pene- 


Bacteria 897 


trate the solid mass and by their vibrations break and destroy the 


protoplasmic molecules. 


Influence of Gravity 

It appears that violent and constant agitation of the liquid 
in which they are living may be injurious to the life of Bacteria; 
but also “sedimentation”—that is, the falling of particles through 
air or water—leads to the freeing of the upper layers of the at- 
mosphere from Bacteria, and also to the purification of large 
sheets of stagnant water, especially when fine mineral sediment 
(as in Clarke’s process for softening water) helps to carry down 
the floating Bacteria. 

The air at the top of St. Paul’s was found to contain eight 
organisms per litre, when that of the churchyard contained 


seventy. Not a single microbe was found in 100 litres of air 
at the top of Mount Blane. Bacteria do not float long in the air. 
They are carried with dust by the wind, but where there is little 
traffic and no wind, as in a quiet room or a meadow in the 
country, the air is practically free from microbes. On the other 
hand, they accumulate on all surfaces, especially on human 
fingers and in liquids. 

It is usual in examining air for the presence of Bacteria to 
pass measured quantities of air through a flask of sterilised 
nutrient liquid mixed with warm (not hot!) jelly, which is then 
poured out on to a sterilised plate, covered, and allowed to 
solidify. Each bacterium present in the air becomes embedded 
in the jelly and multiplies without changing its position, forming 
a “bead” or minute patch of growth. 

The total number of such “patches” thus obtained from the 
measured volume of air can be counted, and the different kinds 
thus captured can be distinguished. Similarly the number of 
Bacteria in measured quantities of water can be estimated. 

For accuracy as to the kinds of Bacteria contained in a 
liquid and their isolation (a matter of the utmost importance to 


VOL.IV--3 


898 The Outline of Science 


the bacteriologist), the fractional method is preferable to the 
gelatine plate method. In the fractional method (used by Lord 
Lister in his study of the bacteriology of milk, when he wished to 
ascertain what different kinds of Bacteria are present in normal 
dairy milk and to separate them from one another for study) 
the number of Bacteria of all kinds present in a cubic millimetre 
of the liquid under examination is counted by spreading it on 
a “squared” glass plate under the microscope. Supposing it is 
found that there are about one thousand organisms present in 
the cubic millimetre, then we dilute that quantity of the liquid 
with one thousand cubic millimetres of pure sterilised water and 
agitate the mixture. Now we have produced a liquid containing 
one organism to every cubic millimetre of its bulk. If a cubic 
millimetre be removed by a graduated dipping-tube, it will 
probably contains a single organism. Fifty such measured cubic 
millimetres may be consecutively removed and placed each in 
a tube of sterilised nourishing or culture fluid. In some no in- 
fection will take place, in a few others an infection by two or 
even three kinds. But in a large majority the experimenter will 
obtain infection by a single microbe, and therefore a pure culture 
of that one kind, which he can proceed to study and to cultivate. 
In the foregoing lines we have given a rough indication of one 
of the methods of the bacteriologist. The difficulty of his work 
consists in the need for perpetual and unsparing care to avoid 
contamination and to leave nothing to chance. 


The Influence of Chemical Agents | 

Apart from the question of nutrition, Bacteria are checked 
in their growth, or actually destroyed, by various substances even 
when present in small quantities. Certain Bacteria cannot 
flourish in liquids giving even a slightly acid reaction; others are 
not so checked. Quick-lime, carbolic acid, free chlorine and 
iodine, and various metallic salts and aniline dyes act as 
“antiseptics,” as they are termed. They kill Bacteria. They do 


Bacteria | 899 


not occur in ordinary natural circumstances, but are made use of 
by man for arresting the destructive action of Bacteria. A 
bactericidal substance has recently been found in the lachrymal 
secretion and other fluids of the human body by Fleming (Proc. 
Roy. Soc, 1922). 

The presence of free oxygen gas is indispensable for the life 
and consequent chemical activities of some Bacteria, which are 
therefore called ‘“‘aérobic” or, better, “aérobiontic.” On the other 
hand, another large series of Bacteria only flourish in the absence 
of free oxygen, and are called “anaérobic” or “anaérobiontic.” 
The chemical action of the Bacteria on the carcasses of dead 
animals and plants and the organic matters contained in the soil 
and infusions (pond water, sludge, ete.) in which they live is 
largely bound up with their dependence on, or their indepen- 
dence of, free oxygen gas. 


§7 

The Action of Bacteria on their Surroundings and especially on 

Organic Matter 

The historic case of the chemical activity of Bacteria is that 
of their causation of the decomposition of the “proteids’—com- 
plex compounds of the five elements Carbon, Hydrogen, 
Nitrogen, Oxygen, and Sulphur, which constitute the flesh and 
softer parts of the bodies of animals and plants. Schwann 
showed that the “putrefaction” of decoctions or infusions of these 
“proteids” such as occur naturally in pools or soil or may be 
prepared as “broths,” takes place only in the presence of certain 
minute organisms living and multiplying in them which were 
called, by him and others, “Infusoria,” but are now distinguished 
from other kinds of microscopic organisms as the “Bacteria.” 
Prominent features of this putrefaction are the production of 
foul-smelling substances and the rapid growth and multiplication 
of the Bacteria. The decomposition effected by the Bacteria is a 
step towards the nutrition of those minute plants, and may be 


900 . The Outline of Science 


compared to the digestion of proteids in the alimentary canal of 
animals. The Bacteria in order to grow and multiply must take 
up into their living protoplasm and assimilate the organic ele- 
ments Carbon, Hydrogen, Oxygen, Nitrogen, and Sulphur, and 
build new protoplasm from them. ‘These elements exist in a 
stable “mineral” state in the atmosphere as water-vapor and the 
gases Oxygen, Nitrogen, and Carbonic Acid gas (CQz2), whilst 
dissolved in all natural waters are Carbonic Acid gas, Ammonia 
(NHs), Carbonate of Ammonia, and Sulphates. All living 
things require the five organic elements as food, but only the 
green plants are able to take them up in this stable mineral 
condition and assimilate or build them up to form elaborated 
compounds, the chief of which are “proteids.” This special 
property of green plants is shown experimentally to be de- 
pendent on the action of sunlight on the green parts of plants, 
the green grains or corpuscles of chlorophyll or leaf-green being 
essential agents in the process, and the liberation of free oxygen, 
necessary for the life of protoplasm, a part of it. No animals 
can build up the organic elements from their simplest condition 
into proteids. Animals are absolutely dependent for the organic 
elements which they require, upon the “proteids” already formed 
by other animals on which they prey, or else on the proteids built 
up as leaves, fruits, and roots by green plants, which also liberate 
during their life perennial supplies of free oxygen gas. Thus 
chlorophyll and sunshine are the indispensable intermediary 
agents bringing the free or lowly combined stable or mineralised 
organic elements into the elaborated condition of proteids and 
protoplasm, whether of plants or of animals, while replenishing 


the atmosphere with free oxygen. 


Ferments 

The Bacteria, like the animals, are totally unable to feed 
upon Carbonic Acid and Ammonia. It is found that there are 
some Bacteria which can get their carbon and their nitrogen 


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= = a ~“"s & 


FIG. 2I.—VARIOUS FORMS OF JELLY-LIKE MASSES (‘‘ZOO- 
GL@A’’ OR ‘‘C@2NOGLGA ’’) PRODUCED BY ENCLOSED 
BACTERIA 


A. A pellicle or skin-like growth enclosing various forms of 
bacteria; at a and d micrococci, at 6 and c rod-like forms (short 
bacilli). B, Egg-shaped ccenoglcea or jelly enclosing large cocci of 
the peach-coloured Bacter1um. C. Net-shaped ccenoglcea of 
the same species. D. Spirillum form in jelly. HE. Curved forms 
(Vibrio) in jelly. #. Arborescent jelly-form of Cladothrix with 
enclosed micrococci. G. Tablet form of growth of Bacterium 
merismopedioides enclosed in jelly (see Fig. 11). H. Jelly enclosing 
spirillum broken into short segments. 


FIG. 22.—A FRAGMENT OF ‘‘ THE GINGER-BEER PLANT ”’ 


Magnified about 600 times linear. It shows (a, a) curved rods and 
chains of short bacilli, enclosed in jelly, very like the sugar-loving ‘‘frog- 
spawn” bacterium called Leuconostoc (Fig. 19); also free bacilli (b, b) and 
yeast-cells (Saccharomyces) (c,c). It is a symbiotic association of three 
distinct organisms. 


rc 


iolols) 


eeRU ses Can Ka) =) 


FIG. 24.—THE FILAMENTOUS 
GROWTHS OF Bacillus anthracis 
PRODUCED BY CULTIVATION OUT- 
SIDE THE ANIMAL BODY BECOME 
SEPTATE, AND EACH SEGMENT 
FIG. 23.—Bacillus anthracis, THE PARASITE OF GIVES ORIGIN TO AN OVAL STATO- 
MALIGNANT PUSTULE OR WOOL-SORTER’S DISEASE SPORE (OR ‘‘ENDURING’’ SPORE) 
(AFTER ROBERT KOCH) 


Three separated spores are seen on 


a, bacilli (free, but not motile); b, red blood corpuscles; the right; two are germinating by a 
c, filamentous or Leptothrix growth-form; d, colourless sprout from the apex or pole of the 
“blood corpuscles. A. From a drop of blood of an in- spore. Contrast with this the germin- 
fected rabbit. B. From the same after three hours ation of the spores of the Hay-bacillus 


cultivation in a drop of aqueous humour. (Fig. 14), which is lateral. 


Bacteria 901 


from a compound so little elaborated as that called Ammonium 
Tartrate; but most of them (as do animals) attack higher 
compounds—breaking them down or digesting them—by the aid 
of ‘‘ ferments”’ or “ enzymes,” which are similar in their action 
to the digestive ferments, pepsin, trypsin, etc., poured out by 
the cells lining the digestive cavity of animals. The flesh eaten 
by an animal is taken into a stomach and surrounded by ferment- 
producing cells, which cause its chemical breakdown. We can- 
not here enter into the questions connected with the nature of 
enzymes and the mode of their action. We must frankly dismiss 
that inquiry to another chapter, merely stating that the ferments 
or enzymes are elaborate chemical compounds of the organic 
elements Carbon, Hydrogen, Oxygen, and Nitrogen, and act as 
what chemists call “catalysts.” The minute Bacteria cannot 
get their undigested food into them, since they have no stomach. 
But conversely they get into their food, and act upon it by 
ferments diffused from their living surfaces, breaking it down 
in various degrees and by various chemical reactions according 
to the kind of bacterium at work and the exact chemical nature 
of the food to be digested. One of the results of this digestion, 
and the most important, is that the food is brought into a soluble 
condition, and the necessary organic elements—in the form of 
“diffusible” compounds less elaborate than proteids—soak into 
the bacterium and are assimilated by its protoplasm which grows 


and reproduces itself. 


Putrefaction 

It appears that in the putrefaction of a dead body, or say a 
piece of meat, there are many kinds of Bacteria at work 
successively. iach is appropriate to a certain step in decom- 
position and produces its special enzyme or ferment. The first 
stage is the production by special Bacteria of compounds from 
the proteids of the meat which are little less elaborate than those 
proteids. No foul smell accompanies their production. They are 


902 The Outline of Science 


called “ptomaines,” and some act as virulent poisons when swal- 
lowed by man. A further breaking-down effected by other 
Bacteria—apparently always ready at hand for this work—now 
leads to the production of foul-smelling compounds—poisonous 
to most animals—known as indol, scatol, ete., the chemical com- 
position and properties of which have been carefully ascertained. 
Following upon this grade of decomposition, we find other Bac- 
teria entering into action. These produce ammonia, sulphuretted 
hydrogen, and carbonic acid. The proteid is thus brought down 
to the condition of low, simple (that is, not complex), compounds, 
chiefly carbonic acid and ammonia. The Bacterium causing the 
ammoniacal decomposition of urine belongs here. Finally, by 
the action of yet other Bacteria the ammonia is oxidised to form 
nitrites and these to form nitrates, so that now the organic 
elements are restored to the stable mineral condition in which 
alone, be it noted, they can serve as food for the green plants. 


Circulation of the Organic Elements 

Thus we see that the Bacteria serve an absolutely indispens- 
able service in the general circulation of the organic elements. 
Were it possible to remove from existence all Bacteria, the 
earth’s surface would be encumbered by the highly elaborated 
proteids forming the dead bodies of animals and green plants, 
and the organic elements would be “locked up” in them. The 
existing “mineral” or “stable” carbonic acid and ammonia would 
in due time be used up and none would be available for the food 
of green plants. Accordingly, no more proteids would be formed 
and no more oxygen liberated to replace that lost by oxidising 
action. ‘The existing proteids would remain undecomposed 
though dead, and the chain of life would be broken. The 
Bacteria, by their putrefying activity, perform the unique part 
of returning the organic elements from their elaborated combina- 
tion as proteids to the simpler stable condition in which green 
plants can again take hold of them and build them into proteids 


Bacteria 9038 


whilst replenishing the vital atmospheric gas—oxygen—continu- 
ally diminished by its union with all kinds of oxidisable material. 

The various Bacteria concerned in proteid putrefaction have 
been to a large extent isolated and their forms and special chemi- 
cal activities determined; but a great deal is still uncertain, owing 
to the minute size of the organisms, their intermixture, and inter- 
actions. 


Species of Bacteria 3 

We cannot yet conclusively arrange the Bacteria into a 
series cf well-defined species and genera, and assign to each 
species its special activities and life-cycle. The bacteriologist 
has, at present, to be content with stating that a given chemical 
change is accompanied by the presence of a longer or shorter or 
straight or spiral bacterium—a micrococcus, a bacillus, a lepto- 
thrix, or a spirillum, which he has isolated in pure culture, and 
as to which he has determined that it does or does not liquefy 
gelatine when growing on it; is or is not “aérobic’”’; does or does 
not produce spores; does or does not produce colouring matter, 
fluorescent or not so; does or does not produce heat or phos- 
phorescence. Further he notes with what reagents it can be 
stained; and how its motile cilia, if it have any, are grouped. 

For convenience a name is assigned to the bacterium in 
each case. The list has become a very large one, comprising, 
according to authorities of moderate views, more than a thou- 
sand “species” and thirty genera. But at present no theory is 
possible as to the origin of these forms, and as to whether they 
all have the persistent character which the species of higher plants 
and animals possess. Nor is there any suggestion as to the ad- 
vantage given to each kind or putative “species” of Bacterium 
by the special and distinctive kind of chemical activity which 
characterises it. The survival in the struggle for existence of this 
or that form or strain cannot at present be accounted for by 
those distinctive activities. 


904 The Outline of Science 


§8 


Manifold Activity of Bacteria 

It is not possible here to do more than mention a few of the 
more striking examples of bacterial activity, especially in so 
far as they affect human welfare. In recent years the investiga- 
tions of specialists in various fields of industry and sanitation 
have resulted in an enormous increase of the kinds distinguished 
and named. Besides proteid putrefaction, many other similar 
processes are accomplished by Bacteria. The decomposition of 
cellulose, the woody fibre of plants, is the constant work of 
certain kinds of Bacteria in ponds and marshes where vegetable 
refuse accumulates, and is accompanied by the liberation of 
marsh gas (CHaz), of sulphuretted hydrogen, and sometimes of 
phosphoretted hydrogen (Fig. 25). The formation of acetic 
acid or vinegar from wine and beer (that is, from dilute alcohol) 
is another bacterial activity (Fig. 6) ; so, too, is the formation of 
butyric acid from milk, and of lactic acid from certain sugars. 
In each case the bacterium concerned is known and pictured, and 
a knowledge of methods of controlling its activity has now 
become essential to the carrying on of great industries, such as 
the manufacture of vinegar, and the protection of wine and beer 
from “souring.” The butyric and the lactic ferments are of. 
essential importance in the dairy industries—souring of milk, 
and manufacture of butter and of cheese. The butyric bacterium 
a few years ago attacked a valuable collection of sea-shells in 
the Manchester Museum, and destroyed many by reducing them 
to a powder, which was found to be butyrate of calcium. 

Many Bacteria produce coloured substances as they grow. 
Usually the colours are obscured by mixture, unless the Bacteria 
are grown in pure cultures. Some Bacteria become themselves 
coloured; as, for instance, the Micrococcus prodigiosus, which 
grows on bread and gives it the appearance of having been 
stained with blood. It spreads over all the bread in an infected 


Bacteria 905 


locality and causes much alarm. Other kinds cause reddening of 
dried cod-fish and of cheese. Another self-coloured kind is the 
Peach-coloured Bacterium, Bactertwm rubescens, which is com- 
mon on dead leaves and twigs in old ponds and also in pools 
above tide-mark on the seashore. Bacteria diffusing yellow pig- 
ment with a green fluorescence into the jelly, on which they are 
cultivated, are common in river water, and others which produce 
blue, violet, and green pigments diffused in the nutrient medium 
in which they are cultivated. One such is responsible for the 
blue-green colour of pus. 

Certain essential chemical changes in the extraction of in- 
digo blue from the indigo plant are due to a bacillus which 
naturally occurs on the leaves of the plant. So, too, the peculiar 
fermentations which give special flavours to different kinds of 
tobacco are due to special Bacteria; as are also the much valued 
flavours of tea and of cocoa. These Bacteria can be encouraged 
or checked by appropriate treatment. 

The manufacture of cheese is dependent on the action of 
lactic-acid-producing Bacteria upon the curd produced by. 
“rennet.” In the later stages of “ripening” both of cheese and of 
butter special flavours are developed by various special kinds of 
Bacteria. Over one hundred species of Bacteria (bacilli and mi- 
erococci) have been described and distinguished which can produce 
lactic acid in milk. Special cultures of Bacteria, giving special 
qualities and flavour to milk or to cream, are carefully prepared 
and used by manufacturers. Bacteria are further important to 
the dairy industries owing to the fact that serious defects such as 


99 6 99 ¢¢ 


“bitter cheese, putrid cheese,” and also “poisonous 


cheese,” as well as similar defects in butter such as “turnip 


red cheese, 


flavour,” “oiliness,’” and bitterness, are due to certain kinds of 
them, and can be avoided by adequate knowledge of what favours 
and what arrests the growth of the several kinds. The flavours of 
cheese characteristic of this or that locality are due to the combined 
activity of many kinds of Bacteria, and of some moulds, a com- 


906 The Outline of Science 


bination differing in each locality and practically peculiar to it. 
As many as eighty different species of Bacteria have been 
described by one investigator as occurring in one kind of cheese. 

“Tanning’’—the soaking of raw hides in liquid by which they 
are converted into leather—is another industry in which different 
Bacteria have at different stages of the process an all-important 
action. They have been very imperfectly studied. 

The cases above cited are a few samples of the many in- 
dustries connected with the preparation of food or animal or 
vegetable substances for manufacturing purposes, in which 
Bacteria are of essential importance, and are being more and 
more studied and brought under control. 

Two very definite and obvious results of bacterial activity 
are (a) the production of heat; and (b) the production of light 
without heat, commonly called phosphorescence. The heating 
of hay and of cotton-waste and of malt is often set up in the 
chemical processes of bacterial fermentation, and under certain 
atmospheric conditions may be so intense as to result in conflagra- 
tion—as it were, a “spontaneous combustion.” 


Luminous Bacteria 

On the other hand, phosphorescence—the production of 
light without heat—is caused by the life and growth of some 
kinds of Bacteria. Many marine organisms, such as the minute 
Noctiluca, jellyfish, sea-worms, crustacea, and shell-fish, as 
well as insects such as the glow-worms and fireflies, are phos- 
phorescent. From any sample of sea-water it is easy by 
appropriate methods of cultivation to obtain a crop of phosphores- 
cent bacilli, which may be kept alive in a flask for an indefinite 
period, and will make the liquid (a meat broth) in which they 
are growing, glow brightly like a lamp when shaken up with 
atmospheric oxygen. Different “species”? of phosphorescent 
Bacteria are distinguished. All appear to be marine or of marine 
origin. Occasionally, all the meat in the butchers’ shops at a 


72) 


FIG. 25.—Vibrio rugula, A FERMENT 

OF VEGETABLE SUBSTANCES, DIS- 

SOLVING THE FIBRE-FORMING CELLU- 
LOSE OF THEIR HARD PARTS 


Magnified 1,000 times linear. A, B, C. 
Slightly undulate, freely swimming. C, D, 
E. Three stages in the formation of the 
statospore, which gives a club-like shape to 
the organism. 


FIG. 27.—Sptrillum ober- 
metert, THE CAUSE OF 
RELAPSING FEVER 


Living specimens in human 
blood. a, a red blood corpus- 
cle. Magnified 1,000 times 
linear. 


FIG. 26—(A) THE ANIMALCULE AMGBA AND (B) A PHAGOCYTE OR COLOUR- 
LESS CORPUSCLE OF THE VERTEBRATE’S BLOOD COMPARED 


In both cases a food-particle a is seen, and its 


‘engulfing’ 


’ 


in the living proto- 


plasm of the microscopic cell—there to be dissolved and digested by ‘‘enzymes”’ or 


’ 


“‘ferments’ 


—possibly a disease-causing one which is thus destroyed. 


—isshown. The food-particle taken up by the Phagocyte is a spirillum 


b, liquid surrounding the 


food-particle engulfed by the Amceba; c, vacuole or liquid holding space in the proto- 


plasm; d, the cell-nucleus. 


FIG. 28.—THE INVASION OF THE ROOTS OF THE 
PEA AND BEAN FAMILY BY BACTERIA 


a, root nodule of the lupin of the natural size, caused by 
Bacterium radicicolum; b, longitudinal section through 
the root and nodule, showing w, the tissue infected with 
bacteria; c, cell from that tissue, highly magnified, showing 
dense infection by bacteria; d, bacillus-shaped bacteria (B. 
radicicolum) from the infected cells, magnified 900 di- 
ameters; e and f, irregularly-shaped bacteria often present. 


FIG. 29.—THE CHOLERA SPIRILLUM, OR COMMA- 
BACILLUS OF KOCH 


a, spirillum stage of growth, with vibrating flagellum, by which 
it is driven along with screw-like movement; b, the spirillum has 
lost its flagellum, and is motionless; it is marked off into separate 
segments; c, the segments have separated from one another as 
comma-shaped pieces, hence the name ‘‘comma-bacillus’’ given 
to it by Koch; d, a number of comma-bacilli of cholera which have 
developed tails of vibratile protoplasm (like a single cilium), and 
are swimming about, being driven by the lashing of these tails. e, 
a cubical packet of the bacterium called Sarcina ventriculi, which 
is found to favour by its presence the growth of the cholera bacil- 
lus in man’s intestine; f, a double row of the spherical units (cocci 
or micrococci), which form a sarcina-packet; g, similar cocci 
separated. 


FIG. 30.—THE Bacillus tuberculosis OF KOCH 


The drawings are 3,000 times the length of the actual specimens, 
and are made from a section of a human tubercular growth 
stained and clarified for microscopic examination. They illus- 
trate the report of a lecture on ‘‘The Warfare against Tubercu- 
losis,’ given by Prof. Metchnikoff before the National Health 
Society, 53 Berners Street, London, W. 


Bacteria 907 


seaside town gets infected and glows in a ghostly way by night. 
Bones and bits of meat lying on a dust-heap become, in warm, 
damp weather, infested in patches with these phosphorescent 
growths. A very curious case is that of the infection of sand- 
hoppers living above tide-mark on a weed-strewn shore by one 
species of phosphorescent bacilli. They were first observed near 
Boulogne and later at Ouistreham on the Normandy coast; but 
have not been hitherto reported from the British shore. The 
phosphorescent bacilli make their way into the blood of the “sand- 


> 


hoppers,” and multiply there to such an extent that the little 
shrimps shine at night like glow-worms, and are, indeed, mistaken 
by casual observers for such. A dozen or so may be picked up 
on a summer’s night as one walks along the sands. They are all 
the more easily picked up since they have become almost incapable 
of crawling, let alone hopping, owing to this wonderful luminous 
infection. The phosphorescent Bacteria cause chemical changes 
in the blood of the sandhoppers of a poisonous nature, in fact 
a disease; and the infected sandhopper rapidly dies. It is a puz- 
zling fact—from the point of view of “the origin of species by the 
selection of favoured races in the struggle for existence”—that 
the two points in which this phosphorescent bacterium, which gets 
into and multiplies in the sandhopper’s blood, arrests our attention 
as differing from any ordinary bacillus, are its power of pro- 
ducing phosphorescent or light-giving material and also of 
producing a poison—deadly to those little shrimps. Yet it 
assuredly requires greater ingenuity than has been applied to 
the case to show that it is of any advantage to the bacillus to glow 
like a glow-worm or to poison the harmless shrimp. How, then, 
did these faculties become fixed in this parasitic race of bacilli, 
faculties which seem likely to be as injurious to its own life as 
favourable to it? It is no advantage to these phosphorescent 
Bacteria (nor indeed to other marine luminous organisms) to 
attract attention to themselves by “lighting up.” All that they 
require in life is a moderate supply of their accustomed food, 


908 The Outline of Science 


which they find in a shrimp’s juices. They do not even profit by 
killing their host. Very few parasites do; they are likely to perish 
with their host. In most cases of parasitism—after a certain 
period, a sort of balance is effected between parasite and host— 
the former does not multiply so as to seriously injure the latter, 
since it is not the host’s death which is beneficial to the parasite, 
but rather the perennial provision by the host of nourishment for 
his guest. We must leave the phosphorescent death-dealing 
parasite of the sandhopper as a puzzle for future inquirers. 

The Bacteria of the sea comprise some kinds peculiar to it. 
The matter has not been very carefully studied, but it has been 
stated that the water of great ocean depths is free from Bacteria, 
and that putrefaction does not occur in those regions because 
there is not a sufficient supply of putrescible matter to maintain 
“a seething pot,” or witches’ cauldron, of endless varieties of 
Bacteria such as are the soil and the more shallow waters of the 
globe. 


Disease-carrying Bacteria; Bacteria Causing Disease 


The poison-producing quality of the phosphorescent bacillus 
brings us to a momentous subject, that of pathogenic Bacteria, 
the study of which has developed of late years into a vast and most 
important branch of medical inquiry. It now appears that nearly 
all “infectious” diseases of men and animals, and many of plants, 
are due to the parasitism in the living body of Bacteria of many 
different kinds. A very few infectious diseases, such as ‘“‘malaria,” 
are traced to equally minute parasites which are regarded as 
Protozoa—that is, of animal nature, rather than vegetable. 
Spreading wherever their special nourishment—dead organic 
matter—occurs, many species of Bacteria infest the skin and 
surface secretions of animals, but beyond causing foul-smelling 
decompositions do no harm. Various kinds have spread from the 
surface into the alimentary canal by way of the mouth, some into 
the bladder and the air passages by way of their external aper- 


Bacteria 909 


tures. The contents of the intestines form a rich culture-ground 
for putrefactive species of Bacteria. Nearly half the bulk of the 
intestinal contents in man and other animals consists of Bacteria, 
including a very large number of distinct kinds, all requiring 
much further study and experiment. Most of these do not cause 
any injury to the host, but may even assist in the process of 
digestion. Poisonous products are often formed by them in small 
quantity and tolerated by the infected host; but from time to time 
(owing to special condition of the host, or to the entrance of 
special malignant species) active poison-producing Bacteria mul- 
tiply in excess in the intestine, and cause deadly disease. ‘Typhoid 
or enteric fever, oriental cholera, dysentery, and various kinds of 
diarrhoea have been thus traced to definite intrusive species of 
Bacteria (Figs. 12, 15 F', and 30). Bacteria (bacilli, leptothrix, 
and spirilla) abound in the mouth and are the active causes of the 
decay of the teeth and toothache. The bacterium which causes 
the ammoniacal fermentation of urine sometimes establishes itself 
in the bladder and produces disease; the deadly tubercle bacillus 
is taken into the lungs, though also entering by the alimentary 
canal; and a putrefactive bacterium makes its way through the 
nose into the air passages in the bones of the face! 

To prove the agency of a particular bacterium as the cause 
of a disease, it is accepted by bacteriologists as necessary to obtain 
in the first place a pure culture of the suspected bacterium and 
then to inoculate with it a perfectly healthy animal previously 
free from it. Then, if the bacterium is found to multiply and 
flourish in the inoculated animal, and the symptoms of the disease 
supposed to be caused by the bacterium appear in the animal, the 
conclusion that the bacterium is the cause or agent of the disease 
is rendered highly probable. But this is not finally accepted until 
it has been confirmed by many trials under varying test condi- 
tions. Many pathogenous Bacteria are able to live, either as 
spores or in active growth and movement, for a greater or less 
length of time, in the soil or water, and so spread from one victim 


910 The Outline of Science 


to another. This is true of the Bacteria causing typhoid, cholera, 
and anthrax (or malignant pustule), and of others; but the 
presence of common putrefactive Bacteria is often antagonistic to 
the life of specialised pathogenous species. Some of the latter 
require the co-operation of other species; e.g. the deadly tetanus 
or lockjaw bacillus, which gets into wounds polluted by rich soil, 
is killed by the phagocytes (see Fig. 26 and explanation) of the 
blood and fails to produce its terrible poison unless it is ac- 
companied (as it usually is) by septicemic Bacteria, which attract 
the phagocytes and so enable the tetanus bacilli to multiply in 
the wound and produce their poison, which is rapidly absorbed. 
Another wound-infection, called “gas-gangrene,” which was 
frequent in the Great War, arises from the co-operation of three 
and possibly of four distinct species of bacillus. Lister discovered 
that the dangerous putrefaction of wounds, whether resulting 
from necessary surgical operations or from accident or from 
hostile assault, is due to the growth in the wounded tissue of 
“septic” or poison-producing Bacteria. He introduced with 
world-famous success the use of antiseptic dressing and great 
cleanliness for the purpose of excluding such Bacteria from the 
wounded surface. 


§ 9 
How Bacteria are “Carried” 


The mode of access of pathogenic Bacteria to the animal 
body is a matter of prime importance. ‘The living tissues are 
protected by the skin, and those Bacteria which cannot gain access 
through the natural apertures to the cavities of the body lined by 
soft penetrable “mucous membrane,” have to pass through the 
dry horny skin by way of accidental cracks and scratches or else 
by attaching themselves to the parasitic insects which pierce the 
skin for the purpose of blood-sucking, such as fleas, flies, bugs, 
ticks, and lice. The germ which causes hydrophobia has not yet 
been satisfactorily identified; but it is established that it is 


Bacteria 911 


brought into man’s body through wounds inflicted by the teeth 
of dogs or other animals suffering from the deadly infection 
of rabies. The hydrophobia germ is present in the rabid animal’s 
saliva. The organism causing typhus or jail fever has been 
shown by experiment to be introduced into man by the louse, 
although it also has not yet been isolated. Yellow fever is due to 
a microbe, probably a bacterium, which is injected into man by 
the stab of a species of gnat, the Stegomya fasciata, but the 
microbe has not been isolated. The bacterium causing trench 
fever is carried by the louse. Relapsing fever (famine fever) is 
caused by a motile Spirillum (Fig. 27), which is carried by the 
common bedbug and is introduced into man by its bite. The 
most terrible of these insect-carried pathogenous Bacteria—look- 
ing as it does like an ordinary short bacillus with nothing peculiar 
about it—is that which causes the historic disease known as 
Plague. It is carried by a wandering species of flea, the Pulew 
cheopis, from the rat to man. 


4 


Pathogenous Bacteria are sometimes “carried”? by higher 
animals, to which they are innocuous. The carrier becomes, as it 
were, a reservoir of a dangerous bacterium injurious to man or 
other animals, but not to the carrier. Such is the history of the 
bacterium which causes “Malta fever.” After its discovery by 
General Bruce it was shown that it infects the goats from which 
the milk-supply of Malta is obtained, and whilst doing them little 
or no injury passes in their milk to the human population, 
especially to the sailors and soldiers in the Government hospital. 
The discovery has led to the supervision of the goats and the 
practical suppression of the dangerous and disabling fever. Not 
unfrequently men and women become insusceptible to the poison 
of typhoid or, in other instances, of cholera bacilli. Such persons 
are found then to act as “carriers” of these deadly germs and 
spread them and infect other persons though they are themselves 
immune. Blood-poisoning of various kinds (pyzmia) is shown 
to be due to specific Bacteria; so are erysipelas, diphtheria, 


912 The Outline of Science 


glanders, various kinds of “catarrh,” and influenza. In the last 
case the bacterium is not yet precisely known and we are con- 
sequently not so well able to deal with it as we may hope to be 
in the future. The disease called “syphilis” is due to a spirillum- 
like form. The bacillus of tubercle (Fig. 30), discovered by 
Koch in 1882, infects various tissues and organs, and multiply- 
ing to excess causes destruction of the lungs, glands, and 
other organs invaded. It is not rapid, though it is sure, in its 
destructive action. Allied to the bacillus of tubercle is that of 
leprosy, even more slow in its growth. It was discovered by 
Hansen of Bergen in 1871—eleven years earlier than the tubercle 
bacillus. The bacillus of leprosy enters the human body from 
infected persons through wounds or ulcerous surfaces. The 
broken skin-surfaces through which it enters are due to a scorbutic 
condition set up by defective diet, such as dried fish, absence of 
fresh meat and vegetables. Wherever the diet of a population 
has improved in these respects, leprosy has died out. Forty years 
ago there were 250 lepers in the leper-house of Bergen (Nor- 
way), now there are on!y some forty or fifty and these are all the 
cases known in Norway. Formerly, in Western Europe, includ- 
ing the British Isles, leprosy was abundant. “Leper-houses,” and 
special lepers’ doors in the churches, were very generally pro- 
vided. There is hope that tubercle (phthisis and its other forms) 
may eventually disappear in a similar way. 

It is not possible to find space here for more than the bare 
enumeration of some of the chief bacterial diseases of man given 
above. Scarlet fever, smallpox, and measles are almost certainly 
bacterial diseases also, but as yet the bacterium responsible in 
these fevers has not been seen and isolated for study. 


§ 10 


Bacteria of the Soil 
Finally, three classes of Bacteria, very important in their 
chemigal action upon water and the soil, must be mentioned. 


Bacteria 915 


They are the Sulphur, the Tron, and the Nitrogen Bacteria. The 
“Sulphur Bacteria” are remarkable for their dependence on 
sulphuretted hydrogen, the gas liberated together with marsh- 
gas in ponds and marshes by the action of the abundant Bacteria 
(above mentioned) which attack and break up the “cellulose” or 
woody matter of vegetable refuse. The Sulphur Bacteria flourish 
by oxidising the sulphuretted hydrogen in such waters, taking 
up the sulphur and storing it as granules in their own protoplasm. 
Peach-coloured or purple Sulphur Bacteria of many varieties of 
form and growth are abundant in stagnant pools, forming wine- 
coloured sheets of encrustation. There is urgent need for further 
study of these peach-coloured Bacteria. Colourless Sulphur 
Bacteria of large size and very distinct shape and growth, in- 
cluding a large range of form, viz. coccus, leptothrix, and spiril- 
lum (known as Beggiatoa), are abundant in natural warm 
springs, which bubble with sulphuretted hydrogen gas. The great 
deposits of pure sulphur in the Tertiary strata of Sicily are due 
to these Sulphur Bacteria. 

The black mud of stagnant pools is due to the production of 
black iron sulphide by the action of sulphuretted hydrogen upon 
iron salts in the soil. “Iron Bacteria” are described which flourish 
in natural waters containing the soluble bicarbonate of iron. The 
Bacteria become thickly encrusted with a reddish-brown deposit 
of ferric hydroxide, and sometimes the supply pipes of water- 
works become clothed with this deposit, due to a chemical attrac- 
tion and oxidation exercised by a special “species” of Bacteria. 

The “Nitrogen Bacteria” are of supreme importance in re- 
lation to the supply of nitrogen in the form necessary as the food 
of green plants. They are one of the chief agents in natural 
waters and in the “soil” and must be regarded as the basis of 
agriculture and all cultivation of green plants. One set called 
the “nitroso-Bacteria” are the agents of the conversion into 
nitrites of the ammonia (NH) which is a final term of proteid 
putrefaction. But nitrites are not what the green plant needs. It 


VOL. IV—4 


914 The Outline of Science 


must have nitrates. A distinct set of soil Bacteria—the nitrato- 
Bacteria—are to hand, and it is they which are concerned in the 
oxidation of nitrites into nitrates. But the green plant’s need 
for nitrogen is yet further met by another and most remarkable 
kind of Bacteria, which can actually seize free wncombined nitro- 
gen from the atmosphere, and convert it into compounds capable 
of feeding the green plant. ‘These nitrogen-seizing Bacteria are 
widely present in “arable” soil. And further, they attack the 
roots of the great food-producing order of plants, the Legumi- 
nos (which includes our Peas and Beans, Vetches, and Clover), 
and entering there cause the growth, on the rootlets, of charac- 
teristic nodules (Fig. 28) in which they accumulate. They are 
known as Bacteriwm radicicolum, and enable the Pea and Bean 
plants to seize and assimilate free atmospheric nitrogen, when 
there is a deficient supply of nitrates from other sources. This 
has been proved experimentally on a large scale. The nitrogen- 
seizing bacterium of the nodules can be cultivated independently 
of the green plant in appropriate solutions, and has been pre- 
pared in quantity as a commercial article to be introduced into 
soils deficient in nitrogenous salts. It yet remains to note in this 
connection that another distinct set of Bacteria is known, and is 
at present the subject of experiment, which has the power of 
deoxidising nitrates in the soil, and yet more remarkable, of 
liberating ammonia and free nitrogen gas. 


Sewage as Manure and as Pollution 


These two subjects each occupy the life-work of many ac- 
complished chemists employed in large public institutions. Great 
works are erected for the purpose of bringing crude sewage into 
the best form for the nourishment of plants by the activities of a 
succession of Bacteria—the putrefactive, the cellulose-destroy- 
ing, the ammonia-forming, the nitrous and the nitrate kinds, of 
which we have briefly written above. ‘That is one vital and 
constantly growing industry. 


Bacteria 915 


Another line of work arises from the necessity of preserving 
some considerable portion of the waters of our streams and rivers 
in such a state of purity as is needful to render it unlikely to pro- 
duce disease when used as the daily drink of a dense population 
of human beings. The water drawn from rivers for human con- 
sumption is liable to contain pathogenous Bacteria, such as those 
of typhoid, cholera, dysentery, etc., especially when the excreta 
of the populations of large towns situated on its banks are con- 
veyed by sewers or otherwise into the river. Legislation has done 
much to prevent the excess of such contamination, which once 
was general. Nowadays the river water supplied by water 
companies is, to a great extent, protected from pollution (under 
Act of Parliament) by the separate treatment of sewage in 
special works; and the water is freed from an excess of Bacteria 
by sedimentation, by precipitation (Clarke’s process), by filtra- 
tion, and by exposure in great tanks to sunlight. In some 
difficult cases chemical purification by ozone or by chlorine has 
been used. The number and kinds of Bacteria present in the 
water at different stages of its passage through the reservoirs 
of the pumping stations are recorded with precision, and 
especial attention is given to the number present (per cubic 
centimetre) of certain indicative Bacteria due to contamination 
by human and animal excreta. Such are the Bacillus coli com- 
munis and the B. enteritidis sporogenes. 'The possible carriage, 
by water thus humanly contaminated, of the Bacteria of typhoid, 
cholera, and other diseases derived from the sewage of a town or 
village where those diseases are present, but not yet notified, is a 
very real danger, and steps are taken by the authorities to pre- 
vent the contamination when discovered. 


§ 11 


The preceding pages may serve to give the reader an outline 
of the extraordinarily varied and vitally important branches of 
knowledge which have grown up, and are still developing, around 


916 The Outline of Science 


the “infusion-animalcules” of Schwann—the “Vibrionia” of 
Khrenberg. The practical demands of human industry and 
sanitation have led to the production of an immense body of 
detailed knowledge as to the chemical activities and life condi- 
tions of many special kinds. But the investigation of those kinds 
not concerned in disease nor in manufacturing processes has been 
comparatively neglected. It is the study of these less specialised 
kinds of Bacteria which will in the future help us to a better 
understanding of the origin and “natural history” of these 
astonishing and ubiquitous organisms. 


BIBLIOGRAPHY 


The reader who wishes to go further into this subject will find the article 
“Bacteriology” in the eleventh edition of the Encyclopedia Britannica, written 
by the late Professor Marshall Ward, the best general statement in English, 
with very full references to earlier important works. He should also read 
Lankester’s articles on “A Peach-coloured Bacterium” in vols. xiii. and xvi. 
(1873 and 1876) of the Quarterly Journal of Microscopical Science. ‘The 
Spaltpilze by Zopf (Breslau, 1885) is a short but well-illustrated treatise of 
great value, whilst the System der Bakterien by Migula (Jena, 1901) is still 
the most detailed work on the subject, giving full references to all the literature. 
Special handbooks dealing with the technical and commercial aspects of 
Bacteriology are published in England and the United States. 

Note.—Pasteur did not distinguish by name and description the various 
kinds of organisms producing the fermentations which he studied. He called 
them all “microbes’—an abbreviation of “micro-bionta’”—a convenient term 
which has come into general use. 


XXVIII 


THE MAKING OF THE EARTH AND THE 
STORY OF THE ROCKS 


4 ' 
ne 


‘ a4 a ¥ pole 
a 7 


e+ oe 7 
SV ant 


ar 
oS als 


THE MAKING OF THE EARTH AND THE STORY 
OF THE ROCKS 


THE EARTH’S INTERIOR—VOLCANIC ERUPTIONS 


Origin of the Earth 
N the opening chapters of this work the modern theories re- 
garding the origin of the earth and its early history were 
briefly discussed. It may. be regarded as certain that the 
earth was originally part of a larger mass from which it, and 
other planets, were heaved off in the form of knotted spiral 
nebule, like many of those to be observed in the heavens to-day. 
One of the two main theories of the origin of the earth and 
the other planets is that of Laplace, according to which the 
planets were formed by the nebule throwing off gaseous rings. 
Professor Chamberlain pictures this hypothesis thus: 


Starting as a gaseous globe, an early passage into a molten 
sphere wrapped in a hot vaporous atmosphere was logically 
assigned the earth. The atmosphere was made vast to con- 
tain all the water of the globe and the volatile matter that 
the heated conditions were presumed to have generated. At 
a later stage a crust was assigned to the cooling globe, and 
the waters, condensing on this, gave the infant earth the 
swaddling bands of a universal ocean. On further cooling, 
shrinkage and deformation were supposed to follow, the 
waters to be gathered into basins, the land to appear, and 
the formation of earth strata to begin. 


Another view is the Meteoric theory, according to which the 


more primitive stage of the nebula was gaseous, but later the 
919 


920 The Outline of Science 


nebule condensed into scattered meteorites, and such bodies as 
the planets were formed by passing through a stage of small 
scattered solid bodies. We quote Professor Chamberlain again: 


Quite in contrast with the older pictures of the primitive 
earth, the planetesimal hypothesis—and this is entitled to be 
taken as the type of theories based on concentration from a 
scattered orbital state—postulates a solid earth, growing up 
slowly by accessions and coming to be clothed gradually with 
an atmosphere and hydrosphere. The earth, the air, and 
the water are made to grow up together from smaller to 
larger volumes without necessarily attaining a very high 
temperature. ‘The sources that at first had furnished the 
body of the ocean and the air, though they fell off as time 
went on, still continued to serve as means of replenishment, 
and to act as an offset to the familiar agencies of loss, far 
down into the later ages. 


The material of the earth is similar to that of many of the 
other members of the Solar System, though of course the 
‘materials may not exist in the same proportion. In its primitive 
stage, the earth in its outer parts was liquid or gaseous; it was 
from its outer part that the moon was detached and became a 
separate body. As we have seen in a previous chapter, the fric- 
tion of the tides has carried the moon farther and farther away 
from the earth. The primitive earth, it is estimated, had a 
diameter of about 5,500 miles; it grew larger by drawing into 
itself more nebulous materials or meteorites (called planetesimals 
by Professor Chamberlain) until it had a diameter of 8,100 miles 
at the end of its growing period. 

After the growing period was over, the earth began to lose 
volume. ‘T'o-day it has a diameter of 7,900 miles. It was cooling, 
and that usually means becoming smaller. It was also consoli- 
dating internally. On the surface the earth was probably like a 
mass of lava, alternately passing from crust-making to boiling 
over. ‘The boiling process must have brought about a sorting 


Photo: Underwood & Underwood 


A SAN FRANCISCO PAVEMENT TORN BY THE EARTHQUAKE 


The result demonstrates the tension and strain produced in the earth’s crust 
by these movements. 


F2nOtOs Ee Nee 
THE EFFECT OF AN EARTHQUAKE IN JAPAN 


A remarkable view of the Nagara-Gawa Bridge on the railway line between Gifu and Ogaki. 


Bhotowi NAA 


THE RUINED BIWAJIMA BRIDGE ACROSS THE RIVER SHONIGAWA, JAPAN 


The bridge now lies in the bed of the river in a curious serpent-like twisted form. 


The Making of the Earth and the Story of the Rocks 921 


of materials, the lighter materials coming to the top and the 
heavier sinking to lower levels. The more acid, granitic materials 
would rise; basaltic materials would sink. Thus, roughly speak- 
ing, arose the rigid, rocky, relatively cool shell of the earth, per- 
haps fifty miles thick, shutting in the internal heat. The 
continents are, on the whole, built of the lighter materials, e.g. 
granites, while the depressions that form the floor of the oceans 
have more of the heavier basaltic rocks beneath them. In any 
case a rocky shell or lithosphere was formed, and the romance of 
the rocks is concerned with the permutations and combinations of 
the materials of the earth’s crust. 

In all probability, the earth contains a metal core embedded 
in a mantle of rocks some 50 miles thick. The centre of the earth 
is about 4,000 miles beneath us; the deepest shaft ever bored 
reached a depth of only some 6,500 feet, or less than one and a 
half miles. For a knowledge of the conditions existing in the 
interior of the earth, therefore, we must depend on the resources 
of scientific investigation. It is probable that the rocky crust 
of the earth changes in its nature at a uniform rate, as the tem- 
perature rises, down to a certain depth, and beneath that there is 
a sudden change in the conditions; we reach the beginning of the 
metal core which is enveloped by the earth’s mantle of rocks. 


§ 1 

The Interior of the Earth 

We owe a great deal of our knowledge of the interior of the 
earth to earthquake waves and to volcanic eruptions. From 
earthquake waves we are able to infer something of the elastic 
properties of the earth’s substance. From such phenomena we 
learn that rigidity increases towards the centre of the earth. This 
is due to the effect of the pressure of the earth’s outer layers, which 
forces the molecules closer together in the most central part of 
the earth. In earthquakes, the earth tremors, starting from the 
focus of the quake, pass through the body of the globe as elastic 


922 The Outline of Science 


waves. The “principal waves” which are felt in a severe earth- 
quake, and which cause the greatest oscillations of the ground, 
pass along the earth’s surface and do not reach a great depth; 
such waves are known as transverse waves and have only half the 
velocity of the longitudinal waves, which are the first waves to 
arrive, and are called “first precursors.” It is these “precursors” 
which tell us most about the conditions of our globe. Their be- 
haviour shows that their paths lie through the body of the earth, 
and from observations it is possible to trace their paths through the 
depth of the globe. There are many seismologic stations at dif- 
ferent places with instruments so fine, and so carefully watched, 
that the earthquake phenomena can be studied with utmost pre- 
cision. By studying the manner of the propagation of earth- 
quake waves it is possible, with the aid of mathematical reasoning, 
to calculate their paths in the interior of the earth, and the velocity 
of their propagation. By such means the condition and the com- 
position of the earth’s interior is ascertained; it is found, as 
already stated, that the rocky mantle or crust of the earth extends 
down to about 50 miles; below that there is a central core of quite 
different and denser metallic material. It is possible that beneath 
the outer solid crust, there exists, at no very great depth, a thin 
molten layer, so thin, comparatively, as not to produce in any 
perceptible degree diminution of the earth’s rigidity. 

It is unlikely that the substratum of the crust is liquid; it is 
merely “plastic.” Mr. Bailey Willis, in discussing “What is 
Terra Firma?” says, “On what do mountains, continents, and 
ocean basins rest? Are there any rocks firm enough to bear the 
weight of mountains or continents without crushing?’ Among 
mountains there are many that are more than three miles high and 
some that exceed five miles. The weight of such a column would 
crush its base. 


Asia is so high that its weight must exceed the load which can 
be supported by rocks, as we know them. The same is true 


The Making of the Earth and the Story of the Rocks 923 


of other continents. It seems reasonable to think [Mr. 
Willis says] that the foundations or rocks beneath the con- 
tinents may approach a crushed condition, or may actually 
be crushed. . . . The crushed condition is not, however, that 
of rocks which fall apart when crushed, for the foundations 
of continents and ocean beds are part of the solid earth and 
are continuous all about the sphere. There is, therefore, no 
space into which any crushed mass can crumble. The 
strength of the rocks may be overcome, but they cannot fall 
apart. This condition has been reproduced experimentally, 
and it has been shown that marble and even the firmest 
granite may be forced to change form, yet to be held a coher- 
ent solid. The rock under these conditions may be compared 
to wax, if only we bear in mind that it remains all the time 
a very strong solid. 


That the temperature of the interior of the earth is very 
high, is shown by the existence of hot springs and volcanoes, and 
by the rapid rise in temperature observed in mining operations, 
tunnelling and drilling. ‘The temperature in the interior of the 
earth, it is reckoned, 


attains some thousands of degrees Centigrade; that the 
material of the earth, nevertheless, does not become liquid 
or even gaseous at such high temperatures, but is proved to 
be very rigid, must be attributed to the extreme pressure 
which packs the molecules together and robs them of their 
mobility. Keeping this in mind while trying to ascertain the 
physical behaviour of bodies with increase of temperature, we 
may infer that the temperature in the interior of the earth 
must certainly remain below 9,000 degrees; in all probability 
it does not even reach 4,000 degrees.* 


§ 2 
Distribution of Land and Water 


The question of the plan of the earth, and the distribution of 
land and water over its surface, is a very fascinating one. More 
* Professor Gregory, The Making of the Earth. 


924 The Outline of Science 


than forty years ago, Lothian Green pointed out that the conti- 
nents correspond in position to the edges and solid angles of a 
tetrahedron—a figure with four triangular faces. ‘The flat faces 
would be occupied by the Atlantic, Indian, Pacific, and Arctic 
Oceans. It was shown mathematically that if water could be 
held by gravity on the surface of a tetrahedron,- so as to cover 
five-sevenths of the area, it would correspond in plan to the oceans 
of the world. It was further pointed out that a sphere, like the 
earth, which was shrinking in volume without changing the area 
of its surface, would assume the form of a tetrahedron; although, 
in the case of a rapidly revolving body like a planet, the angles 
would be very much rounded off. This theory deservedly enjoys 
a great popularity. 

When we consider that animals and plants of the same 
families and even of the same species are found in equal abun- 
dance in widely separated regions, and that this is true of all 
geological ages, we are forced to conclude that continents now 
separated by oceans must once have been connected by bridges 
of land. Oftener than once, dry land has disappeared below the 
surface of ocean water; the bed of oceans has been raised above 
the surface and become dry land; but some areas have continued 
as land throughout nearly the whole of geological time. The 
fabled continent of Atlantis was supposed to have existed in the 
North Atlantic Ocean. Whether Plato’s description of prehis- 
toric Atlantis—and the high state of the civilisation of its inhabi- 
tants—is credible or not, there is little doubt that in very remote 
times there was a large land mass between the Eastern and 
Western Continents. 

It is well established that in the course of time there has been 
a frequent interchange between land and sea areas. Nearly every 
part of England has undergone such changes, land areas have 
been submerged beneath the sea, and alternately the floor of the 
sea has been raised and become dry land. At the time when the 
Coal Measures were formed in Europe, there flourished in 


By couriesy of Messrs. R. W. Munro, Lid. 
THE SEISMOGRAPH 


By means of these highly sensitive instruments, placed in observatories all over the world, earthquake tremors of even a very 
slight character are recorded. The study of the propagation of these tremors through the earth has yielded information about the 
physical state of the interior of the globe that was unobtainable by direct means. 


Photo: Lo Ee A. 


THE HIMALAYAS, SHOWING MOUNT EVEREST 


The summit of Mount Everest, the highest mountain in the world, is 20,002 feet above sea-level. The figure for the greatest 
depth of oceanis rather more. All the heights and abysses which mark the earth’s surface are thus comprised within a vertical space 
of about twelve miles, an insignificant fraction of the radius of the globe. 


Photo: W. A. Green, Belfast. 
MARINE EROSION ON THE IRISH COAST 


Photo: Valentine. 


ARTHUR’S SEAT, EDINBURGH 


The illustration shows a typical example of a rock-mass of volcanic origin. The originally molten substance has solidified into a very 
durable rock able to withstand the action of the eroding agents which have removed the formerly surrounding rocks of softer natures, 


The Making of the Earth and the Story of the Rocks 925 


Australia, India, South Africa, and South America alike, a num- 
ber of distinctive forms of plants. It was therefore concluded 
that all these regions then formed part of an immense continent 
which has been called “Gondwana Land.” But an interesting 
new theory has quite recently been advanced by Professor Wege- 
ner, who suggests that in past ages these continents were very 
much nearer to each other than at the present time. South 
America, Antarctica, Australia, and India can readily be fitted 
round South Africa, like pieces of a jig-saw puzzle, so as to form 
a single land-mass of far less astounding size than the vast “Gond- 
wana Land.” Professor Wegener regards the continental masses 
as blocks of lighter granitic rock, floating, like an ice-floe in water, 
upon a sphere of heavier basaltic rock, which lies below the floors 
of the great oceans, In the Tertiary epoch, not very long ago in 
geological time, these blocks became separated, and America 
drifted westwards away from the Old World. At the present 
day, Greenland at least is moving away from Europe as much as 
50 feet in a year. In front of the moving continent, the rocks 
were deformed and folded into the great mountain chains of the 
Rockies and the Andes, and with this were associated great out- 
bursts of volcanic activity. 


Volcanoes 


We in the British Isles have little experience of earthquakes 
and none of volcanoes. It was not always so. There are many 
records of voleanic eruption in this country; indeed, these Islands 
furnish a great body of evidence regarding volcanic action in pre- 
historic times. Many of the Western Isles of Scotland are partly 
built of voleanic rocks. Central Scotland at one time was the 
eentre of intense volcanic activity; North Berwick Law marks 
one of the chief vents; a great volcano built up Arthur’s Seat and 
the Castle Rock .at Edinburgh; so also with the Eildon Hills in 
Roxburgh and the Cumbraes in the Firth of Clyde, to mention 
only a few. The Cheviot Hills and the Lake District, ages ago, 


926 The Outline of Science 


were also voleanic zones; and in Wales, Snowdon and Cader 
Idris were built up around volcanic centres. 

Throughout geological history there have been great out- 
bursts of volcanic activity alternating with prolonged intervals 
of rest. 

The crust of the earth is subject to strain and stress due 
to the cooling of the earth and to its revolution, while in addition 
the other heavenly bodies may exert an attractive force. Dis- 
turbances of the earth’s crust often produce a movement of the 
strata along fractures or “faults,” a fault being a displacement 
by which rocks are broken across and sink or rise to different 
levels. Rift valleys have been formed by areas settling down to 
a lower level than that of the surrounding region; the Western 
Mediterranean, the Dead Sea, the Red Sea, Tanganyika and 
other African lakes, lie in such areas where depressions have been 
formed in remote times. ‘The upward and downward movements 
of the earth’s crust have given rise to the main configuration of 
the earth. 


The variations in volcanic intensity during successive 
geological periods [Professor Gregory says] may be ex- 
plained as due to the alternation of periods of violent dis- 
turbances of the earth’s crust with periods of slight and 
gentle movements. As the earth shrinks in size the crust 
sags gently downward. For a time the crust may easily 
accommodate itself to the internal contraction, and volcanic 
activity is dormant. As the shrinkage proceeds the crust 
becomes deformed and unstable; and the earth ultimately 
recovers stability by great readjustments of the surface. 
During these movements the crust is fractured and parts of 
it sink, and at such places the pressure on the underlying 
rock is especially heavy. This extra weight on the super- 
heated plastic rock and the opportunity given for its escape 
through the fractures occasion fresh periods of volcanic 
activity. 


Photo: James’s Press Agency. 


FINGAL’S CAVE, STAFFA 


A magnificent example of an igneous rock divided by “‘joints”’ into columns. The rock is a dark-coloured, fine-grained basalt. 
It was not poured out as a lava at the surface of the ground, but made its way between layers of older rocks as a sheet or “‘sill.’’ The 
arch at the entrance is 60 feet high and the cave is 80 yards in length. 


Photo: H. J. Shepstone. 


cOx’s CAVES, CHEDDAR, SOMERSETSHIRE 


Underground caverns are characteristic of limestone formations and are foundin many parts of the world. The constant percola- 
tion and drip of water saturated withlime causes the formation of long stalactites depending from the roof like icicles; drops fall on the 
floor of the cavern untilin time this deposit of carbonate of lime becomes an upright rod called a stalagmite. Sometimes the stalactites 
and stalagmites ultimately join and form complete pillars. 


The Making of the Earth and the Story of the Rocks 927 


Voleanoes are closely related to the earth movements which 
result in the fracturing of strata and folding of the earth’s crust. 
Amongst the examples of periodically active volcanoes to-day is 
Vesuvius. The earliest recorded eruption of Vesuvius (79 A.p.) de- 
stroyed Pompeii, leaving it “a heap of hardened mud and ashes.” 
Stromboli has been constantly active since the time of Homer. 

Sir Ray Lankester, as an eye-witness, has vividly described 
Vesuvius in eruption: 


Vesuvius in Eruption 


The crater or basin formed by a volcano starts with the 
opening of a fissure in the earth’s surface communicating by 
a pipe-like passage with very deeply-seated molten matter 
and steam. Whether the molten matter thus naturally 
“tapped” is only a local though vast accumulation, or is uni- 
versally distributed at a given depth below the earth’s crust, 
and at how many miles from the surface, is not known. It 
seems to be certain that the great pressure of the crust of the 
earth (from five to twenty-five miles thick) must prevent the 
heated matter below it from becoming either liquid or 
gaseous, whether the heat of that mass be due to the cracking 
of the earth’s crust and the friction of the moving surfaces 
as the crust cools and shrinks, or is to be accounted for by the 

_ original high temperature of the entire mass of the terrestrial 
globe. It is only when the gigantic pressure is relieved by 
the cracking or fissuring of the closed case called “the crust of 
the earth” that the enclosed deep-lying matter of immensely 
high temperature liquefies, or even vaporizes, and rushes 
into the up-leading fissure. Steam and gas thus “set free” 
drive everything before them, carrying solid masses along 
with them, tearing, rending, shaking “the foundations of 
the hills,”’ and issuing in terrific jets from the earth’s surface, 
as through a safety valve, into the astonished world above. 


The eruption he proceeds to describe was that of 1871. 


We walked up towards the Observatory in order to 
spend the night on the burning mountain. We found that 


- 


928 


The Outline of Science 


two white-hot streams, each about 20 yards broad at the free 
end, were issuing from the base of the cone. The glowing 
stones thrown up by the crater were now separately visible; a 
loud roar accompanied each spasmodic ejection. The night 
was very clear, and a white firmly-cut cloud, due to the steam 
ejected by the crater, hung above it. At intervals we heard 
a milder detonation—that of thunder which accompanied the 
lightning which played in the cloud, giving it a greenish 
illumination by contrast with the red flame-colour reflected 
on to it by red-hot material within the crater. The flames 
attributed to volcanoes are generally of this nature, but 
actual flames do sometimes occur in volcanic eruption by the 
ignition of combustible gases. The puffs of steam from the 
crater were separated by intervals of about three minutes. 
When an eruption becomes violent they succeed one another 
at the rate of many in a second, and the force of the steam jet 
is gigantic, driving a column of transparent superheated 
steam with such vigour that as it cools into the condition of 
“cloud” an appearance like that of a gigantic pine-tree 
seven miles high (in the case of Vesuvius) is produced. 

We made our way to the advancing end of one of the 
lava-streams (like the “snout” of a glacier), which was 20 
feet high, and moved forwards but slowly, in successive jerks. 
Two hundred yards farther up, where it issued from the 
sandy ashes, the lava was white-hot and running like water, 
but it was not in very great quantity and rapidly cooled on 
the surface and became “sticky.” A cooled skin of slag was 
formed in this way, which arrested the advancing stream of 
lava. At intervals of a few minutes this cooled crust was 
broken into innumerable clinkers by the pressure of the 
stream, and there was a noise like the smashing of a gigantic 
store of crockery ware as the pieces or “clinkers” fell over 
one another down the nearly vertical “snout” of the lava- 
stream, whilst the red-hot molten material burst forward a 
few feet, but immediately became again “crusted over” and 
stopped in its progress. We watched the coming together 
and fusion of the two streams and the overwhelming and 
burning up of several trees by the steadily, though slowly, 
advancing river of fire. Then we climbed up the ash-cone, 


The Making of the Earth and the Story of the Rocks 929 


getting nearer and nearer to the rim of the crater, from which 
showers of glowing stones were being shot. The deep roar 
of the mountain at each effort was echoed from the cliffs of 
the ancient mother-crater, Monte Somma, and the ground 
shook under our feet as does a ship at sea when struck by a 
wave. 

As we ascended the upper part of the cone the red-hot 
stones were falling to our left, and we determined to risk a 
rapid climb to the edge of the crater on the right or southern 
side and to look into it. We did so, and as we peered into 
the great streaming pit a terrific roar, accompanied by a 
shuddering of the whole mountain, burst from it. Hundreds 
of red-hot stones rose in the air to a height of 400 feet, and 
fell happily in accordance with our expectation, to our left. 
We ran quickly down the sandy side of the cone to a safe 
position, about.300 feet below the crater’s lip, and having lit 
our pipes from one of the red-hot “bombs,” rested for a while 
at a safe distance and waited for the sunrise. A vast hori- 
zontal layer of cloud had now formed below us, and Vesuvius 
and the hills around Naples appeared as islands emerging 
from a sea. 


Sir Ray Lankester also witnessed the great eruption of the 
following year. The great lava stream reached six miles down the 
mountain in the flat country below, destroying two villages—its 
course, narrow where it started, widened to 3 miles. After ten 
days “this river, with all its waves and ripples, was turned to 
stone and greatly resembled a Swiss glacier in appearance. A 
foot below the surface it was still red-hot, and a stick pushed into 


a crevice caught fire.” * 


Earthquakes and Geysers 

Some earthquakes are produced as a result of volcanic erup- 
tion, but many of the most severe earthquakes have no immediate 
connection with volcanic activity; they are due to a shifting of the 


1Sir E. Ray Lankester, Secrets of Earth and Sea. 


VOL. IV—5 


930 The Outline of Science 


earth crust, to a movement of the strata along the fractures or 
“faults” to which we have referred. 

Geysers, which are hot springs in which the water is forced 
fountain-wise into the air, exist in volcanic areas, deriving their 
heat from volcanic sources. The most famous are in the Yellow- 
stone National Park, Wyoming, U.S.A. From one of these 
springs the water is shot to a height of nearly 150 feet. Many 
geysers, in America, in Iceland, and in New Zealand—the regions 
where they are best known—do not flow continuously, but squirt 
out jets of boiling water at intervals, which may be remarkably 
regular. The presence of geysers is an indication that the vol- 
canic activity of the district is gradually dying away. 


§ 3 


The Making of Mountains 


We shall see when we come to consider the story of a piece 
of sandstone, how the forces of running water and frost break 
up rocks into fragments, and how the streams sweep these frag- 
ments down into the sea; and we shall see, too, that these forces 
act more powerfully in the mountains than anywhere else. If 
these forces could go on unchecked, they would in time wear down 
the surface of the earth’s rocky crust until it was quite flat. We 
know, too, that the sea covers a much greater area of the earth 
than the land does, and that the highest mountains could be com- 
pletely drowned in the greatest depths of the sea. What is it, 
then, that has saved the earth from being worn into a uniform ball, 
covered all over by a shallow, level-floored sea? ‘The answer is 
that the earth still has a vast store of energy, and as fast as the 
old mountains are worn away new ones arise to take their place. 

There are several ways in which mountains may be built. 
The simplest are those which are mere heaps of material on the 
~ surface of the earth, and these are called accwmulation moun- 
tains. A volcano, for instance, will build up round its mouth a 


By permission of the New Zealand Government Office. 
WAIMANGU GEYSER, NEAR ROTORUA, NEW ZEALAND 


Geysers, or hot springs, are characteristic of regions where former volcanic activity is dying away, and they are found 
notably, in North America, Iceland, and New Zealand. 


The column of water shown in the photograph is 1,500 feet 
high. 


4 
3 
Z4 
| 
: 


~ yy 


ris Bh / 
rd | a aL MUL ‘ 
MMMM rain eB 


FIVE STAGES IN THE MAKING OF A MOUNTAIN CHAIN 


1. A depression forms between two continents. 2. Sediments accumulate. 3. The 
newly made rocks are folded. 4. The folds become more marked. 5. The folds have 
broken and slipped over each other. ‘The next stage is the raising of the folded rocks out 


of the sea. 


fA i = 
TTT LT Va. 


Tami VR, 


eae Ds a en 
ly Rane — TTT LET 


ox 


DIAGRAM SHOWING TYPES OF MOUNTAINS 


IE lee EEC 
SSCL LLL ELLE 


The history of the imaginary country shown above in section is as follows: First was formed a range of folded mountains, whose re- 
mains are seen on the left. This range sank till the sea reached the level S, and new horizontal beds were formed. The country rose 
again and the horizontal beds formed a plateau, which was cut up into relict mountains. To the left remains an original folded mountain, 
never completely under water; then come two relict mountains. Further to the right a younger original accumulation mountain has 
been formed where a volcano has burst through the flat beds of the plateau. 


The Making of the Earth and the Story of the Rocks 931 


cone consisting of layers of dust and cinders and rock-fragments, 
with perhaps sheets of lava which have welled over the lip of the 
hollow or crater thus formed. In this way are built the stately 
cones of Teneriffe, of Fujiyama in Japan, and many others. But 
a volcano is an uncertain and capricious builder, and is at all times 
liable to blow away in a single explosion the accumulated ashes 
of a century of smouldering fires. This has happened more than 
once in the story of Vesuvius in Italy, round whose slopes lie the 
ruins of an older and larger cone. A volcano which has become 
inactive may be so worn away by weathering, that nothing re- 
mains but the plug or neck of rock which hardened in the pipe 
leading down to the molten mass in the interior of the earth. 
Voleanoes are the chief builders of accumulation mountains, but 
small examples may be formed by the piling-up of stones at the 
foot of a glacier, where the ice-stream which carried them melts; 
and if a geologist be allowed to make a mountain out of a mole- 
hill, it is in this group that he must classify it. 

More important mountains, and especially mountain chains, 
are formed, not by the heaping-up of materials on the surface of 
the crust but by warpings and pinchings of the crust itself. 
Sometimes, where the crust is hard, a block of solid rock is raised 
up or tilted all in one piece, as a loose brick may stick up out of 
its place in a brick floor. At other times, where the rocks of the 
crust are newer and more yielding, they are bent and folded into 
a series of waves. 

Folded mountains arise from the crumpling and folding 
along special lines of weakness in the earth’s crust. In front of a 
firm land-mass or continent, the surface sinks, so as to form a 
trough-like depression, which is of course occupied by a sea. Into 
this sea the rivers of the continent which form its shore sweep 
sand and mud washed from the surface of the land. The floor of 
the sea is covered by thick deposits of sandstone and clay, and 
limestone derived mainly from the shells and skeletons of marine 
animals: but the wrinkle in the earth’s surface goes on deepening, 


932. The Outline of Science 


so that the trough is never quite filled. In this way is formed a 
great sheet of sediments, young, soft, and pliable. 

In the next stage this sheet of new rocks is crumpled or 
folded. This is due to pressure, not from above or below, but 
from the sides. When we wish to bend a sheet of cardboard, we 
do not dent it in the centre, we press the two edges towards each 
other till it buckles. If the pressure be only moderate, the folds 
form a series of wave crests and troughs, like those of corrugated 
iron. But if the pressure be very great, the folds are squeezed 
together, they become tall and narrow, and arch over to one side 
like the breakers on the sea-shore. In the end they may lean over 
upon the next fold, so that the whole becomes pleated. The folds 
may even be broken by the strain, and slide over one another. 


The Making of the Alps 

The most important folded mountains of Europe are the 
Alps. The first steps in their formation began at the beginning 
of the Secondary era, when a trough-like sea formed where they 
now stand. Throughout that incalculable length of time, the era 
of the first birds and mammals, of the early flowering plants, 
and of the giant extinct reptiles, this sea was becoming charged 
with enormous layers, thousands of feet thick, of sandstones, 
shales, and limestones. In the next (the Tertiary) era, the con- 
tinent to the south sank below the waters of what is now the 
Mediterranean. ‘This movement was the signal for intense fold- 
ing to begin in the Alpine region. The folds leant over to the 
northwest, and formed sheets of rock lying almost horizontally 
on top of each other. 

The enormous pressures which accompanied these crum- 
plings had their effect upon the nature of the rocks. The clays 
and shales were changed by squeezing into slates and schists; the 
granites were crushed so that their minerals became arranged in 
parallel bands. 

After the folding, the last step was for the crumpled rocks 


ec ee 


See 


Photo: A. Landsborough Thomson. 
GIANTS OF THE PENNINE ALPS 


Monte Rosa (15,217 feet), the second highest summit in the Alps, is seen on the left, the Lyskamm (14,880 feet) in the centre, and 
the Breithorn (13,685 feet) on the extreme right. From the slopes of these huge mountains descends the great Gorner Glacier (left). 
The view is taken from below the Matterhorn, looking eastwards. 


Photo: A. Landsborough Thomson. 
THE MATTERHORN 


s 
This famous Alpine peak is 14,705 feet high. Great glaciers descend from its sides, and 
the sharp outlines of its upper ridges are characteristic of the shattering action of frost. 
For long deemed inaccessible, the summit was first reached in 1865 under the leadership of 
Edward Whymper, but at the cost of four lives during the descent. The mountain is now 
frequently ascended, but its sudden storms, in particular, still lead to fatalities from time 
to time. 


The Making of the Earth and the Story of the Rocks 933 


to be raised out of the sea to their present height. Immediately 
the forces of weathering set to work. Already, in what is geo- 
logically a relatively short time, the surface is transformed. The 
highest summits of the Alps (Mont Blanc, the Matterhorn, and 
others) are formed out of very old rocks, which must have been 
covered by great thicknesses of younger sediments; but, because 
of their hardness, these older rocks have more successfully resisted 
weathering. Only here and there do the crests of the mountains 
correspond with the crests of the folds. The relief of the country 
is determined almost entirely by the sculpturing action of the 
streams of ice and water. 

The ultimate fate of a range of mountains, if the attacks of 
weathering go on unchecked, is to be worn down into a plain. 
Plains may, however, also be formed by the accumulation of even, 
undisturbed layers of sediments; the great plain of Russia, the 
oldest landmark on the map of Europe, is an example. But 
however flat and regular a plain of either kind may be it will not 
yield uniformly to weathering. If a plain be raised up by earth- 
movements into a plateau, its flat surface will soon be cut up by 
river valleys. In the course of time only some surviving peaks 
and ridges will remain. Mountains formed in this way are called 
relict mountains; they are the remains of what was once a tract of 
high land. 


The Mountains of Scotland 

The mountains of Scotland and of Norway are of this type. 
At the beginning of geological history they arose first as a chain 
of folded mountains like the Alps of to-day. Several times since 
then, however, have they been worn down and raised up anew. 
Although the rocks of which they are built are among the oldest 
in the world, the mountains are at the same time very young, since 
they were raised to their present height in the last geological 
period, later even than the Alps. In some disturbance of the 
earth’s crust, these old mountain masses, too tough and hard to 


934 The Outline of Science 


be folded, were tilted up in one vast block. We can see, by the 
lengths of the rivers, that in general the Atlantic side of the block 
is shorter and steeper than the European side. But in both Scot- 
land and Scandinavia, the mountains owe their shape to the action 
of streams of ice and water. 

We see, then, that there are two principal ways in which 
mountains are made. Firstly, there are those mountains which 
are actually built wp, and are known as original. ‘They include 
such types as volcanic cones, which are mere heaps of material, 
like a child’s sand-castle on the beach; and also there are the 
folded mountains, which are portions of the earth’s crust squeezed 
and warped like clay under the hands of the modeller. Secondly, 
there are the relict mountains, which are the remains of former 
high land; they may be considered as monuments of weathering, 
cut from the solid rock. 


The Destruction of Mountains 


Mountains are invariably the scene of intense weathering. 
Rock-fragments once broken off will not accumulate upon steep 
slopes, so that there is no protecting layer of soil, and therefore 
no vegetation. Moreover, isolated peaks are very much exposed 
to all attacks. Lightning may split the rocks of the summits: 
Leslie Stephen, speaking of a shoulder of Mont Blane, says 
“the lightning’s strokes have covered numbers of stones with 
little glass-like beads, showing that this must be one of its 
favourite haunts.’’ But the chief splitter of rocks is frost. Water 
which has penetrated the cracks and joints of the rocks expands 
in freezing, with tremendous force. The angular fragments 
called “scree,”’ which litter the slopes or fill the gullies below the 
crags, are almost all split off in this way. Frost-riven summits, 
like the Coolin Hills of Skye or the “Aiguilles” of Chamonix, are 
sharp and spire-like. 

In the Alps and elsewhere, where the snow lies throughout the 
year in great masses, it becomes hardened and compacted, partly 


The Making of the Earth and the Story of the Rocks 935 


by melting and freezing and partly by its own weight, into ice. 
Mountaineers distinguish between the “black” ice formed by the 
freezing of pools and streams, and the granular “blue” ice made 
of compacted snow. By its own weight and by the pressure of 
the masses of snow, this blue ice begins to creep from the snow- 
fields, down the mountain slopes, down the valleys, in the great 
rivers of ice called glaciers. Nota pile of broken fragments, but 
a solid mass, always welded together by fresh meltings and freez- 
ings, the glacier fills the valley from wall to wall. It is too solid 
to be readily melted, and so it creeps down into the green valleys 
far below the snow-line. It moves infinitely slowly, ten thou- 
sand times more slowly than water, often no faster than the 
minute hand of a watch. From the valley walls blocks of stone 
fall on to the glacier and accumulate there in long heaps called 
moraines; the ice bears them down to the foot of the glacier, 
where it melts, and there the stones are dropped and form great 
heaps. Much of the finer material is washed away by the river 
which the melting ice supplies; a stream which springs from a 
glacier is always exceedingly muddy. 

The action of a glacier in sculpturing the valleys through 
which it makes its way is very different from that of a river. A 
mountain stream cuts a valley, like a furrow cut by a knife in a 
wooden board; narrow at the foot, with sloping sides, V-shaped, 
often very sinuous. ‘The great mass of a glacier acts principally 
by grinding the stones which it carries against the rocks which 
surround it, like a gouge; the valley is U-shaped, with steep sides 
and a wide floor, and no sudden curves. Moreover, a glacier 
rounds off the outlines, and polishes, but at the same time 
scratches the surface of the rocks it passes over. 

All of these features, as well as the abandoned moraines, can 
be recognised in countries where no glaciers now exist, for 
example in the Highlands of Scotland. For in the last geologi- 
cal period, the great Ice Age, all Northern Europe, including 
the whole of Britain north of the Thames, and all Canada were 


936 The Outline of Science 


covered by a vast sheet or sea of ice, like the Antarctic Continent 
or Greenland to-day. The causes of these changes in the climate 
remain obscure. 

We have seen, then, that the regions where the breaking-up 
of rocks proceeds most rapidly are the mountains, the deserts, 
and the cliffs of the sea-shore. On the cliffs, the fiercest attack is 
that of the waves and the pebbles which they carry; in times of 
storm, tremendous blows are struck, and pressures of over two 
tons per square foot are recorded. In the deserts, the rocks 
crack under the influence of the blazing sun alternating with the 
cold of the nights, and under the ceaseless grinding of wind- 
blown sand they are shaped and polished. In the mountains, the 
cold and the freezing of water strike the first blows. Gravity 
alone, or the slow glaciers, or the summer rains, or the water 
that streams from the melting snow when the sun shines or the 
warm Foehn wind blows, carry the fragments away. With long 
periods of rest, as they lie upon level ground or at the bottom of 
lakes, they make their way down to the sea. In the sea, at last, 
they are spread and sorted and hardened into rocks. From the 
sea-floor, they may again be lifted and crumpled into a new 
range of mountains. ‘The weathering will recommence; the 
particles lifted up in the folded strata, ranked and filed in their 
orderly battalions, will find their way back to the sea as a horde 
of stragglers. 

And so mountains are built up and worn down in endless 
succession. ‘There are three stages of mountain-making: the 
forming and hardening of the rocks, the folding, the uplifting. 
There are three stages of mountain-destruction: the splitting, 
the transport of particles, the forming of new rocks; and the 
last stage of the one is the first stage of the other. One genera- 
tion of mountains follows another. To what end? Does the 
earth shrink each time? Is it becoming less round and more 
angular? Are the continents moving away from each other? We 
cannot be sure. Mountains are insignificant wrinkles at best: 


Photo: A. Landsborough Thomson. 


A TYPICAL GLACIER VALLEY 


Looking down the Nicolai Valley from above Zermatt, the Matterhorn being behind the camera. Whereas a valley cut by a river 
is narrow, V-shaped, and tortuous, one gouged out by a glacier is broad, U-shaped at the bottom, and comparatively straight. The 
ice has retreated from this part of the valley, which is now occupied only by the Visp River, fed by the Gorner Glacier and other ice- 
streams which still fill the upper reaches. 


Photo: A. Landsborough Thomson. 
THE GORNER GLACIER 


Where the snow lies throughout the year it becomes hardened and compacted, by re- 
peated melting and freezing, intoice. This, by its own weight and by the pressure of the 
masses of snow creeps down the slopes and valleys in great rivers of ice called glaciers. 
The illustration shows the second largest glacier in the Alps, about a mile wide at this 


point. 


The Making of the Earth and the Story of the Rocks 937 


the highest make no more difference to the earth’s diameter than 
a woollen sock makes to a man’s height: but that they play their 
part in the story of the earth as a whole is certain. Four times, 
since geological history begins, have new generations of 
mountains risen in Europe. There is no reason to suppose that 
the oldest of the four belongs to the first of the great cycles of 
growth and decay in the earth’s history; there is no reason to 
suppose that we ourselves are living in the last. 


§ 4 
A Piece of Granite 

Much of the building material of the continents consists of 
granite, and many of the mountains of the world, such as Mont 
Blane, are granite mountains. We are all familiar with the 
clean, hard appearance of the stone in granite buildings. Let us 
see what the story of this granite is. 

When we look carefully at a piece of granite, the first thing 
we notice about it is that the rock is made up of a number of 
different minerals. As the mixture is rather a coarse one, it is not 
difficult to recognise the more important of these. There are little 
glittering scales and specks of white and black mica; there is a 
great deal of opaque grey or pink felspar, which gives its colour to 
the whole rock; and there are irregular grains of clear, glassy 
quartz. Krom the chemical point of view these three minerals, 
mica, felspar, and quartz, are compounds of the element silicon 
with oxygen and, in the first two cases, with metals such as sodium, 
aluminium, and iron. Although the rock is such a coarse mixture, 
it is, as we know from our granite buildings, exceedingly strong; 
the minerals cannot be separated from each other; they are firmly 
welded together, as the granite worker well knows. This welding 
suggests that the granite rock was formed by the cooling and 
solidification of a mass of liquid rock which had been melted by 
some intense heat. 

Under the solid crust of the earth with which we are more 


938 The Outline of Science 


or less familiar, there lies a layer of rock so hot that whenever the 
pressure is not too great it assumes the molten or liquid condition. 
From time to time, for reasons not well understood, this molten 
rock invades the solid crust above it, and pushes its way out 
towards the earth’s surface. It may reach the surface and be 
poured out as molten lava in a volcanic eruption; or its upward 
rush may be arrested, and it may slowly cool and harden deep 
down in the solid crust of the earth. This hidden eruption may 
be laid bare long afterwards by the gradual wearing away of the 
rocks above: a concealed episode is thus brought to the light of 
day. 


Crystal Making 

When such a molten mass cools and becomes solid, the 
minerals in the rock form crystals. A crystal is an orderly group- 
ing of the molecules or smallest possible particles of the mineral 
upon a definite plan; every mineral when crystallised has its mole- 
cules arranged upon its own particular plan, from which it never 
departs, and which is shared by no other mineral. As a result of 
this systematic arrangement of their minutest particles, all 
crystals have certain properties in common; for instance, a ray of. 
light passing through a crystal is very often split into two, so 
that an object seen through a transparent crystal, say of Iceland 
Spar, will appear double. But the amount by which the two 
rays of light are separated depends upon the particular kind of 
mineral; and if the amount of separation could be accurately 
measured, the mineral could be recognised by this property alone. 

When a crystal can develop freely in every direction it grows 
in a definite geometrical form, a number of flat faces separated by 
definite angles, and by these angles the mineral can be recognised. 
On our piece of granite the light is reflected from the smooth flat 
crystal faces of the mica. But when a molten rock solidifies, the 
crystals will rarely be able to grow quite freely; they will retain 
all their properties except their shape, and will grow as far as 


Photo: W. A. Green, Belfast. 
EVIDENCE OF GLACIAL ACTION 


The slab shows, in a characteristic manner, the polishing effect of 
the passage of moving ice and the scratching caused at the same time 
by particles of harder stone carried by the glacier. The specimen is 
from the Carboniferous Limestone of County Down and is thus 
evidence of a Glacial Period in the British Isles. 


Photo: W. A. Green, Belfast. 
THE GIANT’S CAUSEWAY, COUNTY ANTRIM, SHOWING THE GRAND CAUSEWAY 


This famous Causeway consists of basaltic rock which originated in Eocene times as a molten lava welling up through huge fissures 
and overflowing the land surface. The striking prismatic formation so well seen in the picture has been the subject of much contro- 
versy, but it is doubtless due to contraction strains taking place during the cooling of the mass. Eachcolumnisalso jointed traversely, 


Photo: W. A. Green, Belfast. 


THE PLEASKINS, GIANT’S CAUSEWAY 


Layers of columnar basalt are seen, the results of successive overflows of molten lava. In between are beds of Red Ochre, formed by 
the decay of vegetation in the long epochs which intervened. 


The Making of the Earth and the Story of the Rocks 939 


they can to meet each other in the firmly welded unbreakable 
joints, which we have already noticed in the extraordinarily strong 
granite. 

The size which the crystals attain will depend principally on 
the rate of cooling; the more slowly the molten mass solidifies, the 
longer time will the molecules have to come together and take 
up their positions, and the larger the crystals will be. When a 
molten mass is poured out at the surface in a volcanic eruption, it 
cools very quickly and the crystals may be too small to be seen 
with the naked eye. Sometimes under such conditions crystals are 
not formed at all, and the rock solidifies as a glass, in which the 
various minerals have not separated out. So we can argue that 
glassiness without crystals means rapid cooling—perhaps a 
hundred million years ago. 

On the other hand, since our piece of granite shows crystals 
of large size, we may infer that granite must have cooled very 
slowly. The fact is, it can never have reached the earth’s surface 
at all; and wherever a mass of granite is found to-day, we may be 
sure that it must once have been covered by great thicknesses of 
other rocks, which have been worn.away since the molten granite 
welled up into its present place from the white-hot interior of the 
earth. This, then, is the scientific romance of the piece of granite. 
It burst out of the earth’s internal furnace; it was arrested by the 
crust; it cooled so slowly that its crystals are very big; and they 
were so crowded that they dovetailed into one another, so that 
granite is difficult to break. 


A Piece of Sandstone 

When a mass of granite is laid bare, after unthinkably long 
ages of burial, it will, of course, be attacked in turn by the weather- 
ing agencies which wore away the overlying rocks. In a mountain 
region, for instance, where the granite becomes much exposed to 
the action of the weather and is not much protected by a covering 
of soil and vegetation, the rock will be split and shattered by the 


940 The Outline of Science 


action of frost and perhaps of lightning, it will be worn away by 
wind and running water, and it may be ground to dust by the 
slowly moving ice of glaciers. We must remember, moreover, 
that water may act upon the rocks chemically as well as physically, 
especially if the water contains dissolved acids, such as those 
derived from plant remains rotting in a peat-bog. ‘Thus the 
felspar in a granite rock may be slowly altered into a powder 
which is washed away as mud, while the quartz, which is more 
resistant, will be broken into minute fragments and become sand. 
Below a granite block protruding beside a mountain path, we 
often find a heap of coarse fragments; a little further off angular 
grains of sand lie upon the ground; these are the first stages in the 
breaking down of the rock. 

In a desert region the broken-down particles cannot be 
washed away; but they are blown away by the wind, and the sand 
grains become worn and rounded. Under ordinary conditions the 
rain sweeps the particles into runlets, which lead to streams, and 
these make rivers which bear the weathered particles to the sea. 
In countries with a temperate climate, rivers are by far the most 
important factors in shaping the surface of the land; they operate 
not only by eating away their own floors and banks, but, by re- 
moving the loose particles, they expose the bare rock to the action 
of the weather. As the amount of mud and sand which a river 
can carry along depends on the size and rapidity of the stream, it 
often happens that a river cannot carry as much in the lower part 
of its course as it does higher up where the current is stronger. 
Thus a portion of the load falls to the bottom, though the greater 
part is swept out into the sea where it is deposited, together with 
other material which the sea itself has torn from the coastal rocks. 

All materials laid down under water, by gravity, are called 
sediments. ‘They do not usually accumulate in a continuous way. 
For, after a certain layer of sediment is laid down, all over a con- 
siderable area of the floor of the sea, and of much the same thick- 
ness throughout, there may be an interruption or a change in the 


The Making of the Earth and the Story of the Rocks 941 


supply of material, and the layer next laid down will be distinct 
from the one below it. These distinct layers are geologically 
known as beds or strata. The body of a dead animal, lying on 
the floor of the sea, will be gradually buried by the deepening 
sediments, and its skeleton or shell at least may not have rotted 
away before it is completely entombed. ven inside the rock, if 
the sediment becomes a rock, the hardest parts of animals are 
liable to be dissolved away in the course of time, but an impression 
or mould will be left; or the original material may be replaced, 
molecule by molecule, by some resistant mineral such as silica (of 
which quartz is the crystalline form). Such fossils are of great 
value to the geologist; for the occurrence of a fossil in a rock 
shows that the animal thus preserved was living at the time the 
bed was formed; and in this way the age of the bed of rock can 
be told, in some cases with great precision. 

We are now able to understand what sandstone is. It is a 
compacted deposit of grains of “sand,” worn off the surface of 
some other and older rock (such as a granite), very possibly far 
inland, and carried down by the rivers to be laid upon the sea-floor 
in beds or strata. The loose grains of sand become compacted 
together partly by being cemented by mineral matter dissolved in 
the water, partly by the weight of later sediments above them. A 
sandstone contains, then, two kinds of deposit, the grains and the 
cement. ‘The grains are very largely of quartz, angular frag- 
ments broken off crystals, and, though completely irregular in 
arrangement, retaining their crystal properties; grains of felspar, 
mica, and other minerals also occur. ‘The cementing material 
may be muddy, limy, or of silica, and it is very often stained red, 
yellow, or green; the colour being frequently due to iron, which 
may be derived from many minerals, such as black mica. A whole 
town may have a “local colour,’ depending on the nature and 
staining of the sediments on the floor of an ancient sea which once 
occupied that area. 

Everyone recognises that sandstone is practically very dif- 


942 The Outline of Science 


ferent from granite. It is a plastic building stone, while granite 
cannot be coerced. The textures of the two rocks are as different 
as they well could be. And yet the minerals in a sandstone may 
be the same as those in a granite. ‘This shows clearly that the 
difference in result must be due to the difference in the mode of 
formation. 

Rocks such as granite, which are first formed as molten 
masses below the surface of the earth, are known as Igneous rocks. 
Rocks which are formed at the earth’s surface, as aggregations of 
solid particles, are called Derivative ; and if, as in the case of sand- 
stone, the particles are directly derived from the wearing-down of 
some older rock, the derivative rock thus formed is said to be 


detritic. It is made up of rock-debris, or detritus. 


§ 5 

A Piece of Coal 

To the geologist, coal is a rock, Just as much as granite or 
sandstone; playing a smaller part than either of these in the for- 
mation of land masses, but of great economic importance. It isa 
derivative rock, that is to say it is formed upon the surface of the 
earth; but, unlike sandstone, it is not detritic—not made up of the 
fragments of previous rocks. It consists chiefly of the compressed 
and altered remains of plants, and all rocks which are formed 
through the intervention of plant or animal life are said to be 
organic in origin. Chemically, coal consists chiefly of carbon, 
combined with hydrogen and other gases, and it differs from 
unaltered vegetable matter in containing more carbon and less of 
the other constituents. When coal is burnt in air, the compounds 
of hydrogen and carbon break up; the oxygen of the air combines 
with the carbon to form carbonic acid gas, and with the hydrogen 
to form water; in each of these reactions, chemical energy is set 
free in the form of heat. Where did this energy come from? It 
was stored up by the plants from which the coal is formed; and 
the plants in these far-off times lived as plants do to-day, by 


Photo: W. A. Green, Belfast. 


A MASS OF AMMONITE SHELLS 


A piece of rock from the Liassic strata at Whitby, Yorkshire. It is largely composed of the fossil remains of Ammonites, an extinct 
group of marine animals belonging to the same class of Molluscs as the Nautilus and the Cuttlefish of today. 


Photo: W. A. Green, Belfast. 
A FOSSIL SPECIMEN 


Extracrinus briareus, from the Liassic rocks at Lyme Regis. 
The Crinoids, or ‘‘Feather Stars,’’ are well-known marine 
animals of the present day, but the surviving species are 
greatly outnumbered by the fossil forms which have been 


found. 


Photo: J. J. Ward. 
‘“FOSSIL HORSETAILS’’ OR CALAMITES 


Parts of the stem. These extinct relatives of the modern horse- 
tails attained their maximum development in the Carboniferous pe- 
riod, attaining tree-like dimensions and contributing considerably to 
the formation of coal. It will be seen that the stem is longitudinally 
fluted, with transverse lines at intervals. From these transverse 
nodes side branches arose in whorls. It should be noted that one of 
the modern horsetails, a South American species, sometimes reaches 
a height of 30 feet, recalling the extinct giants. 


The Making of the Earth and the Story of the Rocks 943 


trapping the energy of the orange-red rays of the sunshine. 
George Stephenson said of one of his early railway engines, that 
it was the light of the sun that drove it. 

Ordinary household coal is not the only fuel resulting from 
the transformation of vegetable remains. Peat, for example, con- 
sists of little-altered vegetable residue fermenting in the bogs 
where the plants actually grew. In Lignites the structure of wood 
is still recognisable. Cannel coals and Boghead coals are dull in 
appearance, break irregularly, and are clean to handle. An- 
thracite is also clean, but is shining and metallic, and difficult 
to ignite. ‘These types form a series becoming progressively 
heavier and richer in carbon. But it must not be thought that 
Anthracite, for instance, the heaviest of all, has in its formation 
passed through all these stages. Rather are these different types 
of coal derived from different assortments of plant remains. 

The chief plants of the coal measures were ferns, and giant 
tree-like forms represented to-day by the horsetails and club- 
mosses. Modern horsetails and club-mosses are mostly small 
plants, pigmies compared wtih their predecessors in the Carboni- 
ferous age. Flowering plants were just beginning when the coal 
measures were formed. Coal often shows bands parallel to the 
bedding plane, alternately bright and dull or charred. The dull 
bands consist probably of altered wood and the bright bands of 
leaves and cones. In many cases the coal-seams rest upon beds of 
fireclay, known as the “underclay,” which contains fossilised roots 
and other remains of the plants of which coal is made up. Lime- 
stones, sandstones, and ironstones are also associated with coal, 
and in some places lumps of limestone, known as “‘coal-balls,”’ and 
containing very fine fossils, are found in the coal. 

Although coal is best known from the Carboniferous period, 
scattered deposits occur in rocks of nearly every age. 

The ancient plants which formed the coal measures possibly 
grew in swamps near the sea, like the Everglades of Florida 
to-day. The fallen tree-trunks accumulated, and vegetable 


944 The Outline of Science 


matter may have been carried into the swamp by rivers. The 
land gradually sank, and the swamp was invaded by the sea, and 
beds of sandstone and other sediments were laid down on top of 
a layer of plant remains which became coal. Then the land may 
have risen again, a new forest sprung up on the site of the old 
one, and in time a second seam of coal may have been formed 
above the first one. Sometimes, however, coal may have been 
formed from driftwood, or by the choking of a freshwater pool 
with vegetation. 

Whatever be the origin of the coal, the romance is the same. 
The rough, dirty lumps are the memorials of a silent forest of 
strange trees. They contain the stored energy of the sun which 
shone on these primitive plants. As we saw in a previous chapter, 
they can yield us dyes of all the colours of the rainbow; chemi- 
cally, they are nearly akin to the clear, sparkling diamond. 


A Piece of Chalk 

Chalk is a soft, white, earthy rock, almost pure carbonate of 
lime, but mixed sometimes with various mineral impurities. It is 
made up of the broken skeletons of molluscs, sea-lilies, sea- 
urchins, and the like, but especially of the shells of some of the 
simplest of living creatures, belonging to the group of the one- 
celled animals or Protozoa, and included in the class Foramini- 
fera. ‘Their shells are often smaller than pin-heads, but they are 
extraordinarily beautiful. Chalk is therefore an organic rock: 
but it differs from coal in being made of compounds of lime, not 
of carbon; and in being derived from the remains of marine ani- 
mals, not of plants. There is very little carbonate of lime dis- 
solved in sea-water, but there is a much greater amount of 
sulphate of lime, and various kinds of marine animals, such as 
Foraminifera, are able to transform the one to the other, under 
certain conditions. Animals which require a great deal of carbo- 
nate of lime are confined to clear water and to the warmed parts of 
the globe. 


The Making of the Earth and the Story of the Rocks 945 


When we look at the chalk cliffs of Dover, we are looking at 
the results of the lives of minute Foraminifera, which lived in 
great part floating on the surface of an ancient sea. When they 
died their shells sank slowly to the sea-floor, and there formed a 
deposit. A similar deposit is being formed to-day by similar 
animals over wide areas of the ocean floor, and in another article 
reference has been made to the interest and importance of the 
ceaseless rain of tiny dead creatures that drift down into the 


abysses. 


The Building of a Coral Island 

Other kinds of limestone, less pure than chalk, being usually 
mixed with mud worn off from rocks and stones, consist mainly 
of the remains of molluscs, sea-lilies, and corals, or of Fora- 
minifera different in habit from the chalk-formers. The building 
of a coral island has been described by Professor J. Arthur Thom- 
son (The Study of Animal Life): “We see a multitudinous life 
rising like a mist in the sea, countless millions of microscopic 
creatures often enclosed in beautiful shells of flint and lime; 
myriads of them are always being killed at the surface by vicissi- 
tudes of temperature and the like; they sink gently through the 
miles of water to find a grave in the abysmal ooze. The sub- 
marine volcano top, which did not reach the surface, is slowly 
raised by the rainfall of these countless minutiz. Inch by inch 
for myriads of years, the snowdrift of dead shells forms a patient 
preparation for the coral island. The tiniest, hardly bigger than 
the wind-blown dust, form, when added together, the strongest 
foundation in the world. The vast whale skeleton falls, but melts 
away till only the ear-bones are left. Of the ruthless gristly shark 
nothing stays but the teeth. The sea-butterflies (Pteropods), 
with their frail shells, are mightier than these, and perhaps the 
microscopic atomies are strongest of all. The pile slowly rises, 
and the exquisite fragments are cemented into a stable founda- 
tion for the future city of corals. At length, when the height at 


VOL. Iv—6 


946 The Outline of Science 


which they can live is reached, coral germs moor themselves to the 
sides of the raised mound, and begin a new life on the shoulders of 
death.” 

The living coral is a branched colony of individuals all con- 
nected together and with their soft bodies encased in strong shells 
of carbonate of lime. Each individual or polyp is little more 
than a stomach, with a mouth surrounded by tentacles; each is 
sheltered in a little cup of the limy skeleton which invests the whole 
colony. The branching skeleton assumes beautiful, flower-like 
forms. 

The coral reef builds upwards and outwards. ‘The central 
part is often suffocated, while the edges grow freely, so that when 
the reef reaches the surface of the water it may form a ring- 
shaped island. On this island weathering forms a scanty soil, the 
waves cast up drifted material, the birds rest: in time the new land 
is peopled with animals and plants. “It is a strange and beauti- 
ful story, dead shells of the tenderest beauty on the rugged 
shoulders of the voleano; the slowly laid foundation for the reef- 
building polyps; at last plants and trees, the hum of insects and 
the song of birds, over the coral island.” 


Chemically Formed Rocks 

When a pool of sea-water dries up, the salts dissolved in it 
are deposited on the floor of the basin, and a deposit is formed, 
including common salt and sulphate of lime, or gypsum. On a 
big scale this has often occurred in the past, and we may call 
the results chemically formed rocks. The valuable deposits 
of mixed salts at Stassfurt, in Germany, were formed in this way. 

A peculiar example of a chemically formed rock is found in 
the flints of the lower beds of the chalk itself. Flint is an impure 
form of silica (of which quartz is the crystalline form) , deposited 
from water trickling through the chalk. The water derives its 
silica, not from quartz, which is nearly insoluble, but from the 
flinty skeletons of animals such as certain Sponges and the 


Photo: W. A. Green, Belfast. 


FOSSIL PLANTS OF THE COAL MEASURES 


Remains of the vegetation of former times which have gone to make the 
coal of today: portions of a root and stem (Sigmarilla elegans) from the 


coal measures of the Carboniferous Sandstone at Ballycastle, County 
Antrim. 


Photo: Topical Press Agency. 


THE CLIFFS OF DOVER 


A characteristic example of a chalk formation originally laid down at the bottom of a bygone ocean. The cliffs are largely made up of 
the chalky shells or skeletons of countless generations of marine organisms. 


The Making of the Earth and the Story of the Rocks 947 


Radiolarians (another group of the one-celled animals or 
Protozoa, whose skeletons are more delicate, latticed, and pointed 
than those of the Foraminifera). Very little silica is present in 
sea-water, but these animals possess the power of transforming 
particles of clay (impure silicate of aluminium) into flint, of 
which they build their skeletons. 

We are now able to attempt a rough classification of the 
derivative rocks, namely the rocks made up of materials derived 
from elsewhere. Firstly, according to their composition, there are 
five main types, made up (1) of grains, usually of silica; (2) of 
finer particles of clay; (3) of carbon compounds; (4) of lime 
compounds; and (5) of silica, in solid, flinty masses; with various 
others, less important, chiefly of chemical origin. ‘Then we re- 
cognise three great modes of formation: (A) the detritic, i.e. built 
from inorganic rock debris; (B) the organic, i.e. from remains of 
plants or animals; and (C) the chemical: all are closely linked 
together. These classifications make for clearness of thinking 
but Nature seems to set them at defiance, mixing and mingling, 
in a medley which is at once a puzzle and a fascination. 


A Piece of Slate 


Derivative rocks, too, may be found in greatly altered forms. 
Slate is a rock which can be split into thin slices, and, as everyone 
knows, it can be made smooth enough to write on. Slate is a 
hardened and altered form of clay; and so its classification is with 
the clays and sandstones we have already discussed: it is a detritic, 
derivative rock, made of fragments worn off older rocks. Clay 
is formed by the chemical alteration of felspar, one of the most 
important constituents of granite. The weathering of the granite 
allows water to carry off the altered felspar, and the river or the 
glacier deposits clay in beds. The clay, which ought to consist of 
silicate of aluminium, is usually full of impurities, such as grains 
of sand, and lime. The deposited clay very often hardens in the 
form of shale, a rock which can be split into very thin sheets 


948 The Outline of Science 


parallel to the plane of the beds or strata in which the sediment 
was laid down. 

Slate is a clay or shale in which the original bedding has been 
obliterated by great pressure, in movements of the earth’s crust. 
The mineral particles have been re-arranged in sheets by squeez- 
ing, so that the rock can split into thin flakes. Such rocks are 
called “metamorphic.” 

The clays, it may here be mentioned, have a special impor- 
tance. ‘They are impermeable to water, and therefore hold up 
rainwater which would otherwise sink to such depths below ground 
as to become unavailable. The clays also, by reason of their soft- 
ness, readily decay, with the result that beds of rich soil are 
formed. 

§ 6 
Precious Stones 

When we turn to Precious Stones we are dealing with rocks 
no longer, but with individual minerals. We have considered 
minerals hitherto simply as constituents of rocks; but when we 
consider them by themselves, we take up a new point of view. 
In rocks, the minerals are usually in small crystals; they are often 
impure; they are not free to develop equally in all directions, and 
consequently their shape is irregular. But in studying individual 
minerals, and particularly Precious Stones, we take as our types 
the finest, the purest, and the best-shaped examples to be found. 
We have seen already that when a mineral crystallises, the mole- 
cules or smallest possible particles of the mineral arrange them- 
selves upon a certain definite plan, and this gives certain definite 
properties to the crystals of each mineral. In the study of rocks, 
the properties which are of most use for the recognition of 
minerals are those concerned with the effect of the crystal upon 
rays of light; but in the study of individual minerals, more .ac- 
count is taken of the shape which the mineral assumes. So the 
study of minerals and of Precious Stones is largely a study in 
. crystallography. 


From the Smithsonian Report, 1917. 
A CORAL REEF 


The illustration shows Crescent Reef, outer barrier, Great Barrier Reef of Australia. A fine example of active rock-building by huge 
colonies of coral animals. How the living corals build up coral islands is explained in the text. 


yh 
SO 


Photo: W. A. Green, Belfast. 
THE CASTLES OF KIVVITAR, MOURNE MOUNTAINS, IRELAND 


These ‘‘castles’’ are pillars of naked granite standing on the hillside. Atmospheric weathering has picked out and revealed the natural 
joint planes of the rock. 


Photo: Topical Press Agency. 
A SLATE QUARRY (DINOWRIE) 


This mass of slate was originally a bed of clay, formed from the break-down of older 
rock but was converted into a hard rock by tremendous pressure; its particles have been so 
rearranged that it can be split into thin sheets or slates. 


The Making of the Earth and the Story of the Rocks 949 


What is a Precious Stone? What are the characters that 
give a mineral a commercial value? Generally speaking, and 
making allowance for certain exceptions, they are these: perfect 
purity, and freedom from cracks or inclusions of liquids or of 
other solids, is essential. ‘Transparency, brilliant sparkle, and 
good colour are important; hardness, and the power of resisting 
chemical as well as physical wear, are usually required; and lastly, 
if the stone is to have any market value, it must occur sometimes, 
but only rarely, in fine specimens suitable for cutting. It matters 
not what the chemical composition may be: gems range from the 
Diamond, which is pure Carbon, to the Tourmaline, of which 
Ruskin said that ‘“‘the chemistry of it is more like a medieval 
doctor’s prescription than the making of a respectable mineral.” 
It matters not if the gem be but a variety of a mineral which in 
some other form enters into half the rocks of the world, as 
Amethyst is a variety of quartz; or if it be a strange combination 
of rare chemical elements, to be found only in three or four places 
in the world, like the Emerald. 

Certain stones, which possess the qualities of hardness, bril- 
liancy, and rarity in a marked degree, like the diamond, ruby, and 
sapphire, are always highly prized. But among the less outstand- 
ing gems, vogue and value are largely dictated by fashion, and 
many very lovely minerals are ignored. Among the “semi- 
precious’ stones, the varieties of quartz play an important part. 

Silica, the oxide of the element silicon, occurs most commonly 
in the form of crystalline quartz, which is, as we have seen, an im- 
portant constituent of acid igneous rocks and of all sands. In 
granite, however, it usually forms crystals of extremely irregular 
outline and is often very far from pure. Curious cavities, which 
at one time probably contained gases, are of common occurrence 
in igneous rocks, and they are often lined with large, well-shaped 
crystals. Ordinary or milky quartz is valueless; but the perfectly 
clear Rock Crystal, the purple Amethyst, and the brown 
Cairngorm are all used as gems. Along with quartz, in these 


950 The Outline of Science 


cavities of igneous rocks, there often occur rarer minerals, in whose 
formation the contained gases have probably played a part. 
Amongst these is the valued Topaz, a hard, almost diamond-like 
stone, which may be clear, or of almost any colour except the rose- 
pink with which jewellers not infrequently stain their specimens 
in response to the dictates of fashion. ‘Tourmaline, a stone of 
variable colour as of variable composition, a “little of every- 


> 


thing,” also occurs in this way. Pink and green specimens are 
the most valued, and black is the commonest; while specimens 
occur which show two colours, as red and green, blending into 
each other. ‘Topaz and tourmaline are alike in possessing re- 
markable electrical properties; when heated, they will attract 
fragments of ash or scraps of paper, just as a vulcanite rod or the 
cap of a fountain pen will if it be rubbed. 

Silica occurs not only as quartz, but also combined with 
water, as Opal. Some varieties of this are used as gems and are 
exceptions to the usual rules of gem-qualities; for opal is neither 
very hard nor very resistant, nor is it crystalline. Its play of 
colours, like that of mother-of-pearl but more bright and fiery, is 
due to the presence of a multitude of little cracks, whose angles 
break up the light reflected off the surface. This is called “physi- 
cal” colour, and would, of course, be destroyed completely if the 
opal were ground to powder. The colours of mother-of-pearl, or 
of the golden Iron Pyrites, or of a parrot’s red and blue feathers, 
or of a film of petrol on a pool of water, all depend on the breaking 
up of white light by an irregular surface. But the colour of an 
amethyst, like the colour of blue eyes, is due to the presence of a 
recognisable coloured substance. The amount of an impurity 
necessary to give a tint to a clear stone is so small as almost to 
defy analysis; but we know that it is manganese that gives the 
purple tint to amethyst, and nickel that is responsible for the 
green of Chrysoprase. 

Agate is a beautiful variety of chalcedony, another form of 
silica, which consists of successive layers of different colour laid 


2 4 be oe Y : ~ 7 _ 7 = un 3 AOL eA ~ _ = ; CFE, 
Ke produced by courtesy of Methuen & Co., Lid., from Gem- 1é: y G. F. Herbert Smith. 
PRECIOUS STONES 
Diamond. 8. E rald. 


Diamond (Crystal). 9. Moonstone. 


White Opal. 10. Topaz. 


Ruby (Crystal). 11. Emerald 


Ruby. 
Yellow Sapphire (Orien 


Sapphit 


The Making of the Earth and the Story of the Rocks 951 


down round the walls of a cavity from solution in water. Coat 
after coat is applied, building inwards towards the centre, which 
is not infrequently filled by a few quartz crystals. Cut across. 
the agate shows fine concentric lines, and variations in colour, 
corresponding to each successive layer of material. Onyx is an 
agate with alternate parallel bands of black and white. 


Pearls 

The minerals of derivative rocks are largely the same as 
those found in igneous rocks, but worn and shattered by their ad- 
ventures in the rivers and the sea. New minerals are formed, 
however, by the action of plant or animal life, and a few of these 
are valuable. Red Coral is allied to the reef-building corals. 
Amber is the hardened, fossil resin of pine-trees; Jet is a variety 
of coal. But of all the organically formed gems, one is supreme 
and outstanding, and worthy of a place with the diamond and the 
ruby. In the form of chalk, of limestone, or of marble, carbonate 
of lime is one of the commonest of minerals; but in the form of 
Pearl, its value is as surpassing as its beauty. Pearls are globules 
of carbonate of lime laid down layer by layer by an oyster or 
mussel round some foreign body within its shell (see Colour Plate, 
facing p. 650). They were prized in ancient Egypt, India, China, 
Peru: “In all ages, pearls have been the social insignia of rank 
among the highly civilised,” writes W. R. Cattelle in The Pearl. 
And yet the pearl is soft, easily damaged, and easily tarnished. 
So great is the demand, none the less, that long researches have 
been devoted to furthering the production both of artificial or 
imitation pearls, and of “culture” pearls in the preparation of 
which a foreign substance is introduced into the shell of the 
molluse, round which it may be induced to form a genuine pearl. 


Aristocrats among Jewels 
Four gems may be classed along with the pear! as the aristo- 
crats among jewels: Emerald, Sapphire, Ruby, and Diamond. 


952 The Outline of Science 


All are true “precious stones,” intensely hard, clear, sparkling. It 
is a mistake to suppose that, weight for weight, the diamond is the 
most valuable of these; but the diamond occurs sometimes in large, 
perfect crystals of enormous worth. 

Emerald is a bright-green variety of the mineral Beryl, 
another variety of which is Aquamarine. Large stones of good 
quality are rare; indeed, even small stones of absolute purity are 
very uncommon. Emeralds often show curious variations in the 
colour, which may be much deeper at one part of the stone than at 
another. Many stones sold as emeralds are in reality garnets, 
tourmalines, or other minerals. 

Rubies and Sapphires are varieties of the same mineral, 
corundum, which is the oxide of aluminium. Rubies are deep red, 
while sapphires may be any colour, but are usually blue. Both are 
very hard and rather heavy, and both, like emeralds, occur fre- 
quently in rocks greatly altered by heat or pressure. Rubies vary 
in colour from rose to carmine, and are most valued when they 
possess the tint of “pigeon’s blood”; the colour varies according to 
the direction in which the stone is cut. A perfect ruby of good size 
is worth three times as much as a diamond of the same weight. 


The Diamond 


The Diamond undoubtedly reigns king of all precious stones. 
Not only its great worth and its romantic associations, but also its 
chemical and physical properties give it the lead. Its properties of 
reflecting and refracting light yield an inimitable sparkling lustre. 
It is the hardest substance yet discovered; but it is decidedly 
brittle, and can be burnt away completely, though not melted, 
in the tremendous heat of the electric arc. Formerly, however, 
it was believed to be capable of resisting every attack, and received 
its name of Adamant, or “The Unconquerable.” Chemically, 
the stone consists of the element Carbon, pure and uncombined. 
It is strange indeed that the premier gem of the world should 
be of the same material as the soot of a lamp-chimney or the 


Photo: H. J. Shepstone. 
DESCENT TO THE DIAMOND MINES, KIMBERLEY 


The diamonds are here found in the co-called ‘‘Blue Ground,” a loose, crumbling rock 
consisting of ashes and lavas of volcanic origin. 


Photo: H. J. Shepstone. 


SORTING THE GRAVEL FOR DIAMONDS AT THE KIMBERLEY MINES 


The stones are simply picked out fromthe gravel resulting from the breaking down of the ‘‘ Blue Ground’’ excavated from the mines. 
A diamond is a crystal of carbon, pure and uncombined: it has thus the same chemical composition as lamp-black and as the graphite 
used in pencils, but a different arrangement of the molecules gives it an entirely different physical structure and appearance. 


The Making of the Earth and the Story of the Rocks 953 


graphite of a lead-pencil, only crystallised—that is, with its mole- 
cules arranged in a different way! Carbon enters into the forma- 
tion of every “organic” compound, and the number of its com- 
pounds known to science is far greater than the number of all 
other known substances put together. Each one of us breathes 
out enough carbon every hour, in the form of carbonic acid gas, 
to make a diamond of 100 carats, worth anything over twenty 
thousand pounds! 

Naturally, the question arises, How is this every-day element 
carbon induced to take up this precious form? By difficult and 
costly processes, small diamonds have been produced artificially, 
and the experiment has shown quite clearly that enormous pres- 
sures must play a part in the transformation. In South Africa, 
diamonds occur in a strange igneous rock, a mixture of frag- 
mental ashes and lava, which fills old volcanic pipes. It is sup- 
posed that diamonds were formed during the cooling within the 
pipe of the molten materials thrown up from great depths by the 
voleanic forces. This rock, called “Blue Ground,” is of very basic 
character, and is a remarkable assortment of minerals. It is very 
tough, and after being dug up is exposed to the action of weather- 
ing for twelve months, so that it becomes broken up and the dia- 
monds can be picked out. Some authorities hold, however, that 
the diamonds are deposited from water and are derived from 
organic compounds. 

In other cases the diamonds occur in sedimentary rocks, as in 
sandstone in Brazil, or in loose sand in some parts of Africa. We 
can readily suppose that the diamond resists weathering which 
breaks up the rock in which it was formed, and that it was rolled 
down as a pebble to take part in the formation of the sediment. 

Diamonds in their natural state do not display their full fire 
and beauty, but are irregular in shape and often somewhat cloudy 
or frosted in appearance. ‘To bring out their qualities they require 
to be “cut.” For this purpose they are first split with a diamond 
knife, and then ground on wheels coated with diamond dust. The 


954 The Outline of Science 


stones are cut into various shapes, such as the “rose” and “bril- 
liant,” with different numbers of angular facets. These shapes 
have, of course, nothing to do with the natural crystal shapes, 
which are often eight-sided double pyramids. In addition to its 
brilliance and hardness, the diamond has certain remarkable 
properties, such as that of phosphorescence, or glowing after be- 
ing rubbed or being exposed to light: in the opinion of Sir 
William Crookes, it is the most sensitive substance for ready and 
brilliant phosphorescence. Diamonds are not all clear white; 
they may be of any colour, even deep red or deep blue, though 
these are very rare. 


Remarkable Histories 

The story of diamond-mining abounds in curious incidents. 
The first Brazilian diamonds were used as counters for cardplay- 
ing; the first South African diamond was a child’s plaything. 
Diamonds have been discovered in the walls of houses, and in the 
throats of poultry; more than one fine gem has been thrown away 
as worthless. 

Not less remarkable are the histories of individual stones. 
The huge “Great Mogul,” once the property of the Kmperors 
of Hindustan, has been totally lost; the Koh-i-noor, or “Moun- 
tain of Light,” from the same treasury, was hidden and protected 
by one royal owner after another, even in the torture chamber; 
but its power for evil appears to have passed away, for it now 
reposes among the Royal Jewels at Windsor. Too many dia- 
monds, like the Pitt or “Regent,” have a history of bloodshed 
and cruelty. We remember how, in Kipling’s story, the “King’s 
ankus,” the jewelled elephant-goad, killed six men in a night. 
Even in later days, in South Africa, the diamond has not been 
untainted; but at least the two largest diamonds in the world, 
the “Excelsior” and “Cullinan,” have had a more fortunate his- 
tory. The Cullinan was found in the Transvaal in 1905; it 
weighed, in the rough state, 3,250 carats, or almost one and a half 


The Making of the Earth and the Story of the Rocks 955 


pounds avoirdupois! It measured 414 by 21/4 inches. It was cut 
and ground into nine large and about a hundred smaller stones, 
and the two first parts are by far the largest cut diamonds in 
existence. It is the property of the British Crown. 

Round the diamond, as round all precious stones, strange 
legends and beliefs have gathered. The toad was anciently sup- 
posed to carry a jewel in its head; the dragons which were be- 
lieved to inhabit the Alps were similarly adorned, and the lucky 
man who found a dragon asleep had only to cut out the stone, 
and run the risk of wakening the dragon, to make himself rich 
for life. Gems had all sorts of supernatural properties: they 
cured all manner of diseases, they were charms in love, in battle, 
in peril of all sorts. They were lucky or unlucky, but never 
merely neutral. There were stones for the days of the week, for 
the signs of the zodiac, for the months of the year, for all the saints 
of the calendar. The only element of romance which was over- 
looked was the scientific romance of the origin and properties of 


crystals. 


BIBLIOGRAPHY 


ArsBEr, The Natural History of Coal (1911). 

Cote, Grenvitte, The Growth of Europe (Home University Library) and 
Common Stones (1920). 

Davies, dn Introduction to Paleontology (1920). 

Dwerrynuovss, The Earth and its Story (1910). 

Geixig, James, Structural and Field Geology (1908) and Mountains. 

Grecory, The Making of the Earth (Home University Library). 

Lake anv Rasratu, Tezt-book of Geology. 

Scott, The Evolution of Plants (Home University Library). 

STREETER, Precious Stones and Gems. 


PLoS mdi, Lest 
bs 


XXX 


THE SCIENCE OF THE SEA 


957 


THE SCIENCE OF THE SEA 


The Making of the Sea 
HERE was a time in the earth’s history when there was 
no sea. The surface of the young earth was too hot to 
allow the accumulation of water in basins. More than 
that, there were no basins, for the surface of the young earth 
must have been at any one place as flat as a pancake. If the 
young earth was uniformly spherical (apparently flat at any 
point) there could be no separate seas. If the young earth had on 
its surface a high temperature, there could be no sea: the water 
would evaporate. But there is another factor, which requires 
more explanation than this Outline admits of (see Chamberlin in 
the Bibliography), that the growing earth was originally too small 
to hold even a gaseous envelope (the atmosphere), still less an 
aqueous envelope (the hydrosphere). As the earth gradually 
grew in diameter it acquired an atmosphere—differing from that 
of to-day in having but little oxygen. For the oxygen of our air 
is mostly due to the activity of green plants. As the earth 
reached its limit of growth and began to cool and shrink, a rocky 
shell (or lithosphere) was formed, seething and swaying at first, 
but gradually gaining stability. ‘The probability is that as the 
result of surface boilings lighter materials rose higher to form 
CONTINENTS, while heavier materials sunk lower to form OCEAN 
BEDS. It is probable that over-weighting of vast areas resulted in 
the formation of ocean basins, which have become steadily larger 
as the quantity of water on the earth has increased. Over limited 


areas the floor of the sea has sometimes been raised into dry land, 
959 


960 The Outline of Science 


and a large part of a continent has sometimes sunk down and 
formed the floor of a sea, but the trend of opinion among geolo- 
gists seems to be in favour of the view that the present positions of 
the great masses of land and water have remained on the whole 
the same since continents and ocean basins were first established. 
But this is a much discussed question. It should also be noticed 
that some suppose that there was a universal ocean over the earth 
before there was any dry land. 

To the natural question, Where did all the water come from? 
geology answers, “From the earth itself.” When we visit hot 
springs or watch the clouds of steam rising from volcanoes, we 
probably get more than a hint of how the water of the sea began. 
It is supposed that from a quarter to a half of the present-day 
volume of the seas was in existence before the Cambrian period. 
The rest has been added since—expressed from the earth itself. 
There is, of course, an endless circulation of water, on which the 
economy of Nature largely depends. ‘The mist rises from the 
sea and clouds are formed which condense into rain or snow on 
the cold mountains or in cool strata in the air. The rain falls, the 
springs are fed, the streamlets become rivers, and these return 
to the parent sea. And it is the sun that keeps this water going 
round; for without the sun we could not have either rain or rivers. 


Why is the Sea Salt? 

On an average there are 314 pounds of salty material to 
every 100 pounds of sea-water; and the great bulk of this has 
been dissolved out by the rain from the rocks of the dry land. In 
a very real sense the continents are always flowing into the sea. 
When there is an elevation of part of the floor of the sea, to form 
the chalk cliffs of Dover or the like, we may speak of a restitution 
of material from the sea to the dry land; and a better illustration 
of recoupment going on now may be found in the formation of a 
coral island on the shoulders of a submarine voleano, to which 
reference has been previously made. All the coral-rock, which 


The Science of the Sea 961 


is gradually elevated and in part piled up above the sea-level, 
consists of carbonate of lime which coral-polyps and ancillary 
animals have extracted from the soluble lime-salts of the sea- 
water. But all that the sea has restored to the dry land is little 
compared with what it has filched or with what the fresh waters 
have surrendered. | 

There are dissolved salts and other solids in the water of 
rivers and lakes just as there are in the sea, but those in the latter 
are nearly 200 times as abundant as those in the former, so we 
speak of fresh water and salt water. More than three-fourths 
of the salts in the sea consists of common salt (sodium chloride), 
which forms 77.7 per cent. Magnesium chloride forms 10.8 per 
cent., and the same percentage is made up of the sulphates of 
magnesium, calcium, and potassium. ‘That leaves only 0.7 per 
cent. for calcium carbonate, magnesium carbonate, magnesium 
bromide, and traces of other salts. ‘There are so many marine 
~ animals with heavy shells of carbonate of lime—think of oysters 
and periwinkles alone—that one is surprised to find so little of 
this salt (0.3) in solution in the sea. The explanation is that the 
carbonate of lime used in shell-making is largely formed, as the 
result of some process of chemical change in the tissues of the 
animals, from the fairly abundant calcium sulphate (3.6 per 
cent.). There is a far smaller proportion of silica in sea-water 
than in river-water, and the explanation must be that the silica 
gets locked up in the siliceous skeletons of flinty sponges and of 
the beautiful microscopic plants called diatoms which float near 
the surface. 

In 100 lb. of average sea-water there are 314 lb. of salts, 
and this is the “average salinity.”’ But different parts of the sur- 
face of the sea differ markedly in salinity, for it will increase 
where evaporation is great (as in the Red Sea); it will decrease 
where the rainfall is heavy; it will decrease where there is little 
wind and much precipitation. In a general way, the salinity 
corresponds with the climate. 


Vor. 1v—7 


962 The Outline of Science 


A very interesting fact in regard to the salts of the sea is 
their correspondence with the salts in the blood of land animals! 
If the percentages of sodium, magnesium, calcium, potassium, 
and chlorine in sea-water be compared with the percentages in 
blood serum, the figures are respectively 30.5 and 39; 3.79 and 
0.4; 1.2 and 1.0; 1.11 and 2.7; 55.27 and 45.0. There are striking 
resemblances especially in the proportion of potassium and cal- 
cium to sodium. So it has been suggested by Macallum and 
Quinton that in Cambrian times an equilibrium was established 
between the living matter of marine animals and the composition 
of the surrounding water. To use Sir William Bayliss’s words: 
“When vertebrates with a closed circulatory system took to the 
land, they took with them a blood of the same composition, as re- 
gards salt, as the sea-water which they left behind.”’ And as to 
the differences which the percentages we have quoted also reveal, 
these may be interpreted in terms of the changes in the compo- 
sition of the sea since the close of the Cambrian period. The 
composition of our blood is a tell-tale relic. 


The Depth of the Sea 


The total surface of the globe occupies about 197,000,000 
square miles, and about 71 per cent. of that (namely 140 millions) 
belongs to oceans, seas, and lakes. The great mirror of the sea 
seems very uniform to the landsman’s eye, but it is really very 
heterogeneous. For there are shallows and depths, and apart 
from the floor the surface has its ups and downs. This is due to 
a variety of causes, but notably to the gravitational pull of the 
continents, which implies a heaping-up of the waters round the 
shores. The surface of the Mid Indian Ocean is thus lowered by 
the Himalayas. 

Thousands of soundings have been taken all over the navi- 
gable globe, and we know that the average depth of the sea is 
about 2144 miles. Only 16 per cent. of the ocean-floor lies be- 
tween the shore-line and 1,000 fathoms; more than half the entire 


Photo: Copyright, Daily Mail. 


HIS SERENE HIGHNESS ALBERT, PRINCE OF MONACO 
(b. 1848) 


A veteran Oceanographer, who has conducted many marine | 
expeditions, the results of which have been published in a monu 
mental series of monographs. He has founded an Oceano- 
graphical Institute in Paris and a magnificent museum and 
laboratory at Monaco. He has made great contributions to; 
the science of the sea. 


Photo: Elliott & Fry, Lid. 


THE LATE SIR JOHN MURRAY 


One of the naturalists on board the Challenger, and after- 
wards editor of the great series of Challenger Reports. A 
strong personality, instinct with the scientific temper, reso- 
lute and indefatigable in overcoming difficulties, he must be 
reckoned as one of the founders of Oceanography. He dis- 
covered the valuable deposits of Christmas Island and wasa 
generous patron of scientific endeavours, such as the Millport 
Marine Station. He was the greatest authority on Deep Sea 
Deposits. His Oceanography in the Home University Li- 
brary is a remarkable piece of work,and his Depths of the Sea 
(along with Dr. Hjort) is also outstanding. 


Re produced by courtesy of the purchaser, the Prince of Monaco, and the artist. 


A NEW WORLD FOR THE LANDSCAPE PAINTER—AT THE BOTTOM OF THE SEA— 


HAS BEEN OPENED UP BY AN ARTIST, MR. ZARH PRITCHARD, WHO PAINTS 
UNDER WATER IN DIVING DRESS 


The picture shows pointed rocks at the bottom of the sea, a submarine ‘‘landscape’”’ from 
a study in oils painted 16 feet under water. 


The Science cf the Sea 963 


floor is covered by depths between 2,000 and 3,000 fathoms. Sir 
John Murray gave the name “deeps” to holes and basins, troughs 
and trenches, with a depth of over 3,000 fathoms. Thus there is 
the “Challenger Deep” (5,269 fathoms) in the north-west 
Pacific, and the “Swire Deep” (5,348 fathoms) off Mindanao. 
Of this tremendous abyss—400 feet more than six miles—Sir 
John Murray wrote: “If the highest known mountain (Mount 
Everest in the Himalayas, 29,002 feet) could be placed in this 
area of the Pacific, its summit would be covered by the waters of 
the ocean to a depth of 3,087 feet.” From the bottom of the 
“Swire Deep” to the top of Mount Everest would be a vertical 
distance of 61,091 feet, or over 1114 miles. This is surely the 
limit in the irregularity of the Earth’s crust. 


ya 


Temperature of the Sea 


Heat rays are lost at about 250 fathoms, and even in the 
tropics the upper stratum of warmish water is comparatively thin. 
The great bulk of the water in the oceans is relatively cold. There 
is an automatic regulation at the surface, for when the tempera- 
ture rises there is increased evaporation which checks the rapidity 
of the rise; and if the temperature is lowered a blanket of water- 
vapour forms over the surface which checks the rapidity of the 
fall. E'rom one place to another there is great diversity of tem- 
perature, but at any given place there is, apart from the surface 
stratum, great constancy of temperature year in year out. 
Murray and Mill write: 


At the depth of 50 fathoms it is probable that the tempera- 
ture does not change by so much as 2° F. at any one place 
throughout the year; and below the depth of 100 fathoms 
there is no evidence of any annual change of temperature 
whatever. 


Sir John Murray calculated that on the average all the 
water in the ocean deeper than 500 fathoms may be said to have 


964 The Outline of Science 


a temperature below 40° F., and that this would include about 
87 per cent. of the entire ocean. But in the great depths the 
temperature is lower still; it is Just a little above the freezing- 
point of fresh water (32° F.). Eternal winter reigns. “The 
ooze dredged from the ocean floor in the tropics is so cold that 
it cannot be handled without discomfort.” ‘This low temperature 
is mainly due to a slow northward “creep” of the ice-cold waters 
of the Antarctic. 


Pressure in the Sea 

When a piece of wood is weighted, lowered to a great depth, 
and pulled up again, it will no longer float. All the minute 
cavities in the wood have been burst in and filled with water. The 
log of wood is thoroughly waterlogged, and gives one a hint of 
the enormous pressure at great depths. It is calculated at 214 
tons on the square inch at a depth of 2,500 fathoms. And yet 
we know that a frail skeleton like that of Venus’s Flower-basket 
(see Figure facing p. 121) stands like a fairy palace on the floor 
of the deep sea, and that it is surrounded by the delicate shells of 
creatures that once lived on the surface. How is the apparent 
contradiction explained? 

The pressure is due to the weight of the water which packs 
the molecules a little more closely together. If an open glass 
vessel is lowered into the water it at once fills, and as the pres- 
sure of the water is the same inside as outside nothing happens. 
If a corked bottle not quite full be lowered to a great depth, one 
of two things will happen—the cork will be stove in or the bottle 
will be shivered. 

What is known as “Buchanan’s experiment” is very instruc- 
tive in this connection. It arose out of the fact that two ther- 
mometers lowered from the Challenger (1873) in 3,873 fathoms 
collapsed owing to the great pressure. Mr. J. Y. Buchanan, the 
physicist on board, took a glass tube, sealed at both ends, wrapped 
it in a cloth, and enclosed it in a cylindrical copper case with the 


The Science of the Sea 965 


ends pierced with holes to let the water in. The case was sent 
down to a depth of 3,000 fathoms and then pulled up. The 
copper case looked as if it had been struck with a hammer at the 
portion occupied inside by the sealed glass tube. And as for that 
glass tube, it was represented inside the cloth by what looked 
like snow—the glass reduced to fine powder! 

Let us quote the explanation given by Sir John Murray, 
who witnessed the experiment. | 


It seems that the sealed glass tube, while sinking, had held 
out long against the pressure, but this at last had become too 
great for the glass to sustain, and the tube had suddenly 
given way, being crushed by the violence of the action to a 
fine powder. The collapse had been so rapid and complete 
that the water had not had time to rush in through the holes 
at either end of the copper cylinder and thus fill the empty 
space caused by the collapse of the glass tube, but had in- 
stead crushed in the copper wall and thus brought about 
equilibrium. ‘The process, which is exactly the reverse of 
an explosion, is called an “implosion.” 


When a body of any kind sinks to a great depth any cavities 
it may contain will be quickly filled with water; but if there are 
cavities which cannot be quickly reached, like water-tight com- 
partments, they will be imploded, and the form of the body will 
be altered correspondingly. There is no warrant at all for the 
common sailor’s belief that ships and men sink till they “reach 
their level” and there remain suspended! Everything sinks to the 
bottom. 

When a deep sea fish rises in pursuit of its prey above its 
usual zone, the decrease of external pressure brings about an 
expansion of the gases in the swim-bladder, and the specific 
gravity of the fish is greatly reduced. The result is that, in spite 
of its efforts, the fish “tumbles upwards” to the surface, killed 
sooner or later by the distension of its organs. This is an 
explosion. ; 


966 The Outline of Science 


§ 2 


Movements of the Sea 

The sea is eternally restless. Even when there is no wind at 
all, there may be a “swell,” for the perfect elasticity of the water 
keeps it throbbing long after the storm is past, Just as the gong 
continues quivering long after the blows have fallen. Attention 
has already been given to the tides (p. 290), which are due to the 
gravitational attraction of the sun and moon, sometimes acting 
together, sometimes against one another. ‘The familiar ebb and 
flow of the tides, two low tides and two high tides in every 24 
hours 50 minutes, are coastal expressions of two worldwide tidal 
waves, which ceaselessly chase one another round the globe. In 
equatorial waters the tidal wave would travel at the rate of 1,000 
miles an hour if there were no obstructions, but it must be clearly 
understood that what travels so quickly is the undulation, not the 
water. “The waving grain, as it bends to the breeze, causes an 
undulation that travels across the field faster than you can run; 
but the stalks are rooted; they only sway backward and forward 
to the breeze. So is it with the deep sea and its swell” (Maury 
and Simonds). The tidal undulation and the familiar rise and 
fall must be distinguished from tidal currents produced near the 
shores and often attaining so great a speed (6-11 miles an hour) 
that people use the word “Trace.” 

When a sea is shut off by a narrow entrance or by a break- 
water of islands from the influence of the almost worldwide tidal 
wave, there will be little ebb and flow, as is well illustrated by the 
practically tideless Mediterranean. When the configuration of 
the coasts heaps up the tidal current interesting phenomena may 
result, such as the 70-feet tides of the Bay of Fundy and the 
40-feet tides of the Bristol Channel. In rushing into a river the 
tide may form a dangerous “bore” or “eagre,” a wall of foaming 
water, sometimes over 10 feet in height (see the picture of the 
Trent eagre facing p. 290). 


The Science of the Sea 967 


We cannot leave the tides without noticing that they have 
engrained their periodicity in the constitution of some of the 
shore animals—a fact of special importance since many of the 
great stocks of animals seem to have served an apprenticeship in 
the littoral area. Ages of reacting to the tidal rhythm have left 
their mark on many a shore animal, and probably on some that 
have long since passed beyond the sound of the sea. The small 
green worm Convoluta comes up on the flat beach at Roscoff 
when the tide goes out, and disappears into the sand when the 
tide comes in. Removed to the laboratory and placed in tall 
vessels half filled with sand and half filled with water, the little 
creatures continue for a considerable time moving up and down 
as the tide outside ebbs and flows. The rhythm of the tides has 
become an organismal rhythm. 

When a tidal current is split into two by a rocky island, and 
these meet again, a whirlpool is sometimes formed—a vast vortex 
of angry water. One of the best examples is Corrievrekin in the 
Sound of Jura, where two rapid currents, from the north and the 
west, meet around a pyramidal rock which rises rather abruptly 
from a depth of 100 fathoms to within 15 feet of the surface. 
There is a true vortical movement, such as we see in miniature 
in an eddy on the downside of a rock which breaks the current 
in ariver. Whirlpools have taken a grip of man’s imagination, 
and their terrors have been exaggerated. The famous Charybdis, 
in the Straits of Messina, which thrice a day sucked down the 
water of the sea and anything that sailed thereon, is not a whirl- 
pool at all, but a “chopping sea” due to the oblique action of the 
wind on a tidal race or rapid which changes its direction with each 
ebb and flow. Of course it remains dangerous enough, but it is 
not a whirlpool. The same remark applies to the not less famous 
Maelstrom between two of the Lofoden Islands; it is a race, not 
a vortex, and it is habitually navigated. Edgar Allan Poe’s 
description of its down-sucking powers is a splendid piece of 
exaggeration. 


968 The Outline of Science 


§ 3 

Circulation in the Sea 

Almost as important as the circulation of the blood to the 
body is the circulation of the sea-water to the welfare of the 
globe. Through the direct and indirect influence of the sun, pro- 
ducing changes of temperature, density, and wind, the waters of 
the ocean are in ceaseless circulation. ‘This is an extremely diffi- 
cult subject, and it may be enough here to distinguish the slow 
vertical movements in the mass of water and the more rapid 
horizontal movements of the surface stratum in drifts and cur- 
rents. The Gulf Stream is a much-talked-of instance of an 
important oceanic current, which, as Dr. H. R. Mill says, “is 
often spoken of as if it were a phenomenon by itself, whereas it is 
really only part of a great system of surface circulation, the water 
whirling as if stirred in the direction of the hands of a watch in the 
northern Atlantic, and if stirred in the opposite direction in the 
southern part of the ocean.” The almost resting centre of the 
North Atlantic whirl forms “the calm, weed-hampered water”’ of 
the Sargasso Sea. It embraces several hundred thousand square 
miles and is covered with a flotsam of seaweed wrenched off from 
distant shores. It remains to-day where it was when Columbus 
encountered it on his first voyage to America. ‘There are four 
other great weed-hampered areas of little motion, but this is the 
Sargasso Sea. 


Storms at Sea 
It seems almost a bathos to write in cold blood of storms at 
sea. 


Part of the water surface [as Dr. Mill puts it] yields to the 
stress of the wind striking it obliquely, and is depressed, 
thereby ridging up the neighbouring portions and orginating 
a wave, the form of which advances as a line of rollers before 
the wind. Only the form advances, for while the particles of 
water in the crest of the wave are moving rapidly forward, 


— 


Reproduced by courtesy of the artist and the Galeries Georges Petit, Paris. 
SHOWING A BASALT TUNNEL ON THE SEA-BED 


’ 


ANOTHER SUBMARINE ‘“‘LANDSCAPE,’ 


Photo 2a eAs 


AT CAPSTONE HILL, ILFRACOMBE 


On a quiet day the waves of the incoming tide seem to rush in, but in most cases it is only the wave form that advances. Particular 
masses of water merely rise and fall. On entering a shallow area near the coast a tidal wave may be changed into a current. More- 
over, the lower zone of the water is retarded by contact with the bottom, and the upper part breaks in spray. A breeze often blows 
the crests off the waves, and a steady wind may cause a stratum of water to slip before it. With this horizontal movement there will 


also be associated vertical movements in the sea. 


The Science of the Sea 969 


those in the trough move back to almost exactly the same 
extent. Thus rollers merely lift and lower the vessels that 
float upon them. 


When these waves “reach” a shallow the lower part in contact 
with the floor is retarded, and the upper part curves into what 
often looks like a flinty cave and then breaks into spray. These 
breakers have great eroding power—-blasting and hurling off 
huge pieces of rock or carving the cliffs with a battery of gravel. 
Dr. Mill gives a quarter of a mile as the greatest length of a 
wind-wave from crest to crest, and fifty feet as the maximum 
height. But the bell of a lighthouse on one of the Isles of Scilly 
was wrenched off by a breaker at a height of 100 feet. It should 
be noted that even the largest waves are very shallow in their 
grip and have hardly any appreciable effect below 100 fathoms. 

There are other storms due to the wind driving a thin stratum 
of the surface water before it, either inshore or offshore. Earth- 
quakes and volcanic eruptions may also raise huge waves. A 
whirlwind is an aerial vortex or eddy caused by the meeting of 
two winds, and a whirlwind at sea may cause a waterspout. This 
consists of a pillar of cloud rising from sea to sky, whirling on 
its axis, round a core of low pressure, and moving over the surface 
of the deep. The water at its base is fiercely agitated as if it 
were boiling, but there is no sucking up of more than the spindrift 
from the waves. 


§ 4 


The Floor of the Sea 


A comprehensive survey of the globe leads us to distinguish 
three great areas. First, there is the continental area, including 
(a) the elevated plain, with an average height of about 2,250 
feet above sea-level, (b) the shallow water shelf around the con- 
tinental islands which are insulated parts of the mainland, as 
distinguished from oceanic islands which originate as volcanoes 
from the floor of the sea, and may become the foundations of 


970 The Outline of Science 


coral reefs. (See THE MAKING OF THE EARTH AND THE STORY 
OF THE ROCKs.) 

Second, there is the continental slope, from the shallow water 
shelf down to the bottom of the sea, occupying about one-sixth of 
the total superficial area of the globe. 

Third, there is the abyssal area, the floor of the deep sea, a 
prodigious plain of about 100 millions of square miles. It seems 
to be on the whole a monotonous plain, with undulating slopes 
like sand-dunes, interrupted by occasional volcanic cones rising 
towards or even to the surface, and by occasional troughs and 
basins—the “deeps” already referred to. 

It is believed that the earth’s crust (or lithosphere) beneath 
the oceans, like that of the continents, is superficially ““parcelled 
out into great earth-blocks, separated from each other by faults 
and fissure lines, along which volcanic action and gaseous emana- 
tions take place, and through which massive outflows of molten 
matter occur” (Murray). ‘The continental crust has been ex- 
plored by borings and mines to depths of several thousand feet, 
and geologists consequently know a great deal in regard to what 
is hidden below the surface. As to the abyssal crust, however, 
the dredge cannot penetrate beyond the deposits, and the nature 
of the submerged crust has been inferred rather than observed. 
Some information is afforded by comparing the materials ejected 
from oceanic and from continental volcanoes; the former appear 
to be heavier and more basic, the latter lighter and more acid in 
composition. (See THE MAKING OF THE EARTH AND THE STORY 
oF THE Rocks.) ‘The continental earth-blocks tend to rise; the 
abyssal earth-blocks tend to subside. 


Deep-sea Deposits 

In the shallow water, or comparatively shallow water, of the 
littoral area and the upper parts of the continental slope, the de- 
posits on the floor are very diverse, varying from place to place 
according to the nature of the shore rocks, the materials the 


The Science of the Sea 971 


rivers bring down, and the character of the marine vegetation and 
animal life. Thus there are gravels, sands, muds, and masses of 
organic matter. 

On the floor of really deep water there is an accumulation of 
fine-grained ooze, consisting very largely of the calcareous and 
siliceous remains of minute organisms which have sunk down 
from the surface. Thus there is “Globigerina ooze,” predomi- 
nantly made up of the pinhead-like shells of surface Foramini- 
fera, comparable to those that formed a great part of chalk de- 
posits in the distant past. This Globigerina ooze has a pale- 
grey colour, sometimes reddened with iron oxide, or tinged brown 
with manganese. It is said to cover an area of 47,752,000 square 
miles at a mean depth of 12,000 feet. In other areas there is a 
predominance of the shells of “winged snails” (Pteropods), or 
of siliceous Radiolarians, or of siliceous diatoms—all derived from 
the surface waters overhead—and thus there are different varie- 
ties of ooze. Along with the remains of organisms, both from the 
surface and from the floor itself, there may be, of course, particles 
of volcanic dust and meteoritic iron, as well as minute fragments 
from the land-rocks and precipitations from the sea-water. 

Over an immense area of 55,000,000 square miles, almost 
equal to the whole land-surface of the globe, there is a slowly 
accumulating deposit of “red clay’—the insoluble residue and 
final form of all the sea’s dust. No “red clay” has been recognised 
among continental sedimentary rocks; indeed, chalk is the only 
continental rock which can be traced back to an ancient ooze. 
What should be inferred from these facts is still uncertain. 


Soli’ 
The Life of the Sea 
There is probably far more living matter in the sea than 
there is in all the rest of the world. Spenser was right in speak- 
ing of the sea’s “abundant progeny, Whose fruitful seede farre 


972 The Outline of Science 


passeth those on land.” As the animals of the sea have been dis- 
cussed in the chapter dealing with adaptations to environment 
(p. 115), we need not now do more than make the general 
economy clear. The visible rays of the sun can penetrate to 500 
fathoms, and the actinic rays further, so there is a vast area within 
the sun’s appreciable influence, and this is the area of productivity. 
Here are the great floating sea-meadows. No doubt, there is 
great importance, especially in the shallower waters, in the or- 
ganic fragments which are broken off from the larger shore sea- 
weeds and from the sea-grass (Zostera), or borne down by rivers, 
but the microscopic green alge of the open waters play a funda- 
mental part. By their photo synthesis they set agoing the up- 
building of complex carbon compounds from the raw materials 
of air and sea. They are devoured by small animals, and, as we 
have seen, there is a long ladder of incarnations—from diatom 
to mackerel. There is also a ceaseless rain of moribund animal- 
cules and of sea-dust from the surface-zones downwards to the 
abyssal ooze. Nor can we forget the part that green organisms 
play in helping to oxygenate the surface waters of the sea, thus 
making it a possible home for ordinary animals like crustaceans 
and fishes. 

The most important impression is that of the abundance of 
minute forms of life, linked together in nutritive chains. Sir 
William A. Herdman writes: 


It may be recorded that Brandt found about 200 diatoms 
per drop of water in Kiel Bay, and Hensen estimated that 
there are several hundred millions of diatoms under each 
square metre of the North Sea or the Baltic. It has been 
calculated that there is approximately one Copepod [a 
minute Crustacean] in each cubic inch of Baltic water, and 
that the annual consumption of these Copepods by herring 
is about a thousand trillion; and that in the 16 square miles 
of a certain Baltic fishery there is Copepod food for over 
530 millions of herring of an average weight of 60 grammes. 


The Science of the Sea 973 


Well might Spenser say: “So fertile be the floods in generation, 
So huge their numbers, and so numberlesse their nation!” 


The Bacteria of the Sea 

As is made clear in Sir Ray Lankester’s article on Bacterta, 
these microbes play a very important part in the economy of the 
sea. They are inconceivably numerous wherever there is abun- 
dant organic matter, except, perhaps, in the great depths, for we 
know almost nothing of deep-sea bacteria. ‘They are, in any case, 
least abundant in deep and cold water, and most abundant in 
shallow water or where cold and warm currents meet. One of 
their headquarters is certainly the thickly peopled “mud-line,” 
where at a certain distance off shore the organic sea-dust settles 
down to form fine mud. 

The marine work of bacteria is in the main threefold. Some 
of them—by putrefaction and fermentation—convert the excre- 
tions and dead fragments of animals into carbonate of ammonia. 
This may be utilised by marine plants, but it becomes more 
readily available when changed by oxidation into nitrites and 
nitrates. This is the work of the nitrifying bacteria, and where 
there is abundance of them the minute marine alge flourish in the 
waters. But there are other bacteria which reverse what is done 
by their neighbours. ‘They reduce nitrates to nitrites, nitrites to 
ammonia, and ammonia to free nitrogen. So their work lessens 
the amount of nitrogen that can enter into the cycle of life. For 
there are only two or three ways, e.g. by the root-tubercle bacteria 
of certain plants, that free nitrogen can be utilised by living 


creatures. 


Colour of the Sea 

Part of the fascination of the sea is in its changeful colour- 
ing. It is “eternally new.” ‘lo some extent the colour is due to 
reflection from the sky; “but the fact that blue and even indigo 
blue may be seen with overcast sky, while the deep blue is not 


974 The Outline of Science 


observed in the Arctic waters, even with bright sunshine, proves 
that this is not the sole cause” (‘Tarr and Martin, p. 653). A 
long tube of distilled water has a blue colour, and the addition of 
impurities changes this to green. It is probable, therefore, that 
the bluest sea, e.g. of the Gulf Stream, is the purest, and that the 
greenest, e.g. of the Arctic Ocean, contains most extrinsic ma- 
terial. It is all a question of the reflection of different wave- 
lengths of the white light. The extrinsic material consists of the 
minute organisms of the Plankton, e.g. reddish Alga in the Red 
Sea, and suspended sediment brought down by the rivers, e.g. 
in the Yellow Sea off the Chinese coasts. The colour may also 
be affected by differences in the salinity and in the amount of dis- 
solved gases. In shallow water, e.g. among the coral reefs, 
reflection from the coloured floor will also count. 

In the article on ELectric AND LUMINOUS ORGANISMS, at- 
tention has been directed to the frequent “phosphorescence”’ of the 
sea both on the surface and in the depths. There is often a welter 
of sparks in the wake of the vessel, and the oars of the rowing- 
boat drip fire in the summer darkness. Apart from some phos- 
phorescent bacteria, the light-producing organisms of the sea are 
all animals—of every degree up to fishes; and the display often 
beggars description. There is a suggestion of it in “The Ancient 
Mariner,” but the term “sea-snakes” must not be taken literally: 


Beyond the shadow of the ship, 
I watched the water-snakes; 
They moved in tracks of shining white, 
And when they reared, the elfish light 
Fell off in hoary flakes. 


Within the shadow of the ship, 
I watched their rich attire, 
Blue, glossy green, and velvet black, 
They coiled and swam; and every track 
Was a flash of golden fire. 


In the well-investigated case of the small open-sea crustacean 
called Cypridina, the luminescence is associated with the action 


THE GULF STREAM HAS CLEARLY DEFINED ‘‘BANKS’’ OF WATER 


Observe the dividing-line between the Gulf Stream and the colder ocean water. It leaves the Gulf of Mexico through 
Florida Strait as a river of very salt warm water, fifty miles wide, with a velocity of five miles an hour. Off Cape 
Hatteras it curves eastwards and spreads across the Atlantic. Branches diverge northwards and reach the British and 
Norwegian coasts, while the main body passes southwards to join the north equatorial current off the Canaries. This 
north equatorial current is due to the Trade Winds blowing from the coast of Africa. 


Photo: J. W. Knight. 
; A WATERSPOUT 


‘ 


When a whirlwind occurs on the sea, the result is a “‘waterspout’’—a whirling pillar of 
cloud stretching from sea to sky and moving along like a dust-whirlwind on land. At the 
base of the great aerial eddy the sea is violently churned as if it were boiling, and spray may 
be carried up. It is a popular fallacy that the sea-water is sucked up in a solid mass. A 
waterspout on land is usually a torrential shower. 


DEEP-SEA DEPOSITS; THE SHELLS OF MINUTE CREATURES, KILLED AT THE SURFACE, SUNK INTO THE OOZE 
OF THE OCEAN FLOOR 


1. Pure chalk ooze made of the sunk shells of pinhead-like animals (Foraminifera) which live at the surface. 

2. Mixed ooze consisting of a variety of shells and fragments of shells. 

3. Pure Radiolarian ooze—the flinty shells of small creatures which live at the surface and sink down as they are killed by vicissitudes 
of temperature and the like. The living matter that remains associated with the minute shells forms an important part of the outside 
food-supply of the abyssal animals. 


AN ENLARGEMENT OF A YOUNG FORM OF AN ABYSSAL FISH (STYLOPHTHALMUS) FROM VERY DEEP WATER 
IN THE INDIAN OCEAN 


The eyes are borne on the end of long stalks; the optic nerve and four of the eye-muscles show asimilarelongation. The darkspots 
shown on the front of the head are probably the nostrils. The adult form of the fish is not known, but it is probably one of a family 
(Stomatidz) which have ‘‘telescope eyes,”’ i.e. with the axis of the eyes considerably elongated. 


The Science of the Sea 975 


of a ferment, luciferase, which operates upon and brings about 
the rapid oxidation of a light-producing substance, luciferin. But 
we do not know what this means in the physiological economy of 
the animal’s body, or what use, if any, the light may have in the 


creature’s everyday life. 


Ice in the Sea 

In the Far North the winter sea is covered with ice, heavier - 
than freshwater ice because of the salts, but still able to float and 
to bear the sleds of the Eskimos and the explorers. ‘Tidal and 
other currents break the sheet into pack ice, which may be piled 
up into little mountains. In the Arctic summer when the sun does 
not set, the ice-plain breaks up into floe ice, which drifts south- 
wards in a long procession and gradually melts. Both in the 
Arctic and in the Antarctic an ice-foot is formed as a fringe along 
the land, partly marine and partly terrestrial in origin. Quite 
different are the icebergs, which are the broken-off lower ends 
of glaciers and are therefore fresh. These huge masses may rise 
100-200 feet above the water, but that is only one-sixth to one- 
seventh of their total height. When the submerged part melts 
much more rapidly than the exposed part, the iceberg may be- 
come top-heavy, and “turn turtle.”” As the icebergs drift south- 
wards they become a menace to ships, the most terrible of the 
many tragedies being the wreck of the Titanic (April 14, 1912), 
when 1,517 persons lost their lives. It must be realised that 
icebergs are often great floating islands, several miles across, and 
that they play an important part in transporting sediment, and 
in affecting the salinity and temperature of the sea as they melt. 
Their climatic influence penetrates far inland in countries like 
Labrador and Nova Scotia. 


The Uses of the Sea 
In many ways the sea makes the earth more liveable. It 
absorbs the heat of the “tropical sun” and distributes it far and 


976 The Outline of Science 


wide. It tempers the great heat by currents of ice-cooled water 
from the Poles, and by cold water rising from the wintry depths. 
It is the cradle of many of the winds which do so much for good 
as wellas ill. It is the central depot in the incalculably important 
circulation of water; it is the beginning and the end of rivers. Its 
give and take—absorption and restoration—of atmospheric gases 
makes for uniformity in the composition of the air. It is the 
universal clearing-house, the universal cleanser. In the sea all 
waste is reduced to its common denominator, and the results of 
the wear and tear of the earth are laid down in deposits which 
might again become rocks. Finally, the sea yields man a rich 
harvest; it has always been one of his great schools; and it binds 
together much more than it separates. 


The End of the Sea 

There was a time, as we have seen, when there was no sea. 
The elements that unite to form water (H2O) were imprisoned 
in the mineral matter of the molten crust, and later on there was 
water-vapour in the hot atmosphere. Gradually the earth passed 
into what has-been called the terraqueous phase of its evolution 
or development. But if the supply of heat from the sun becomes 
in the course of ages less and less, the earth will become cold like 
the moon, and colder. The sea will become as hard as rock, — 
frozen from top to bottom, “and over this will roll an ocean of 
liquid air about forty feet in depth.” Unless, indeed, something 
else happens to this earth of ours. 


§ 6 
Denizens of the Sea 
In the chapter on ADAPTATIONS TO ENVIRONMENT something 
has been said of the animal life and the plant life of the sea. 
As has been explained, there are littoral, pelagic, and abyssal 
marine animals, peopling the shore-area, the open sea, and the 
deep sea respectively. Similarly, as regards plants, there is 


The Science of the Sea 977 


the very important shore-vegetation of seaweeds and sea-grass 
(Zostera), the broken fragments of which are borne seawards 
to serve as a fundamental food-supply for multitudes of fishes, 
molluses, crustaceans, and worms on the floor of relatively shal- 
low waters. On the other hand, there is the pelagic population 
of floating Algw, more or less microscopic, on which the daintier 
open-sea animals, like crustaceans, feed, while others sink down, 
as they die, to the plantless abysses. 

In this chapter on the science of the sea we must bring in 
the animals again—the sea’s abundant progeny; and we begin 
with the OPEN SEa. 


Open-sea Animals 

Our first picture may fittingly be devoted to whales. Every 
age has had its giants, and the giants of to-day are the whales, for 
the Sperm Whales and the Right Whales may be fifty feet long, 
and there are others larger still. It does not seem certain that 
the Toothed Whales and the Whalebone Whales form one order, 
which would mean that they have had a common ancestry; for 
the fact is that a superficial resemblance is apt to blind us to 
a multitude of detailed structural differences. It is possible that 
whales evolved twice. But whether once or twice, they almost 
certainly evolved from terrestrial ancestors, as their vestiges of 
hind-legs, for instance, seem to indicate. Suckling the offspring, 
as whales of course do, could not have begun in the sea. But the 
adventure of the Cetacean pioneers, which led to a change of 
habitat from shore to sea, must have begun millions of years 
ago, the whale’s adaptations to marine life are so numerous and 
so penetrative. 

What a bundle of fitness is a whale: the torpedo-like shape, 
the almost frictionless skin, the tail turned into a propeller with 
horizontally flattened flukes, the balancing flippers made out 
of fore-limbs, the blubber that conserves the precious animal 
heat and makes the great mass of the body more buoyant, the 


VOL. IVv—8. 


978 The Outline of Science 


position of the valved nostrils on the top of the head so that air 
may be more readily inhaled when the creature comes to the 
surface of the sea, the relatively huge chest-cavity and lungs, 
the almost invariable reduction of the number of offspring to 
one at a time, and the special milk reservoirs which give the 
young one a big mouthful at once. 

The toothed whales feed on true fishes and on cuttlefishes; 
but the whalebone whales feed on small open-sea animals, such 
as the lightly built molluscs known as sea-butterflies, which are 
caught in the great cavern of the open mouth on the frayed 
edges of the baleen plates. In rushing through the water with 
the mouth gaping the baleen whale would be apt to drown itself, 
were it not that it is able to shunt forward the spout-like open- 
ing of the windpipe into the posterior opening of the nasal 
passage on the roof of the mouth. Thus no water can go down 
the wrong way! 

At first sight a whale seems hairless, but in most cases 
groups of hair can be seen about the snout, jaws, and skin. As 
some embryo whales show numerous hair-rudiments on the front 
part of the body, it seems safe to conclude that the ancestors of 
modern whales had hair like other mammals. And the interest- 
ing point is that the hairs which remain are sometimes more than 
tell-tale evidences of the past; they are actually of use as tactile 
structures. In the Right Whale they are extraordinarily well 
ennervated, four hundred nerve-fibres sometimes going to a 
single hair. They illustrate the conservatism of evolution— 
that an ancient structure may be kept hold of as long as it 
is of use. On the other hand, when the use has quite gone the 
structure may entirely disappear, as has probably been the case 
with the whale’s ear-trumpet and third eyelid. In some embryo 
whales there are two button-like projections that look like the 
last traces of externally projecting hind-limbs; and it is im- 
pressive to see the deeply buried vestigial thigh-bone of a North 
Atlantic Right Whale—it is only 5 inches long! 


The Science of the Sea 979 


On a sea voyage the “spouting” of whales is a familiar 
sight. It means that the used-up air is blown out very forcibly 
from the nostril, perhaps half a dozen times in rapid succession, 
and that the water-vapour in the breath condenses into drops 
in the cold air, sometimes accompanied by a little spray borne 
up by the blast. Spouting water is of course impossible, and 
Milton was not very happy in his remark “And at his gills draws 
in, and at his trunk spouts out, a sea.” A Right Whale may 
remain under water for twenty minutes, which is a marvellous 
feat for an air-breathing animal. Of the creature’s vast 
strength some indication may be obtained from the record of 
one which was struck in the early morning off Nantucket, and, 
heading out to sea, towed a boat with six men in it for seven 
hours and eventually got free. It took the men five hours’ 
hard pulling to get home. 


§ 7 

Marine Birds 

From among the marine birds we may select two—the 
penguins and the puffins. Quainter creatures than penguins it 
is hard to find, but their adaptiveness is not less striking. They 
have sacrificed their wings to form the powerful swimming 
flippers which strike the water like springy oars, and enable 
the birds to dive to a depth of ten fathoms; they can toddle on 
the ice, toboggan on the snow, and climb a cliff to a height of 
700 feet; they can fast for four weeks when they are nesting; 
they can survive for several weeks within a snow-drift; year 
after year they find the Antarctic shores from afar although 
their flightlessness keeps them on the surface of the sea. 

Another bird that spends much of the year on the Open 
Sea is the puffin, a quaint member of the well-defined family 
of auks. 


The puffin [Dr. Townsend writes] is a curious mixture of 
the solemn and the comical. Its short stocky form and 


980 The Outline of Science 


abbreviated neck, ornamented with a black collar, its serious 
owl-like face and extraordinarily large and _ brilliantly 
coloured bill, suggestive of the false nose of a masquerader, 
its vivid orange red feet and legs, all combine to produce 
such a grotesque effect that one is brought almost to 
laughter on seeing these birds walking about near at hand. 


They come to our steep shores at the beginning of summer, to 
mate and breed, and in one locality in the Hebrides Professor 
Newton estimated the attendance at about three millions. One 
egg, white in colour, is laid in the recess of a yard-long burrow; 
it hatches in about a month and the young bird has to be fed for 
four or five weeks. We see the parents bringing fishes in their 
bills (shaped like the coulter or foreiron of a plough), and it 
is difficult to understand how the number is added to without 
losing previous captures. It may be that the tongue and some 
spines in the mouth keep hold when the jaws are opened. 

There are reptiles of the Open Sea, notably certain fish- 
eating turtles like the Hawksbill, the Loggerhead, and the 
Leathery Turtle, all of which have to go back to the sandy shore 
in order to lay their eggs, Just as the land-crabs have to return 
to the sea. For the Natural History rule—with some explicable 
exceptions—is that animals go back to their old headquarters 
when they start a new generation. ‘Then there are the genuine 
sea-snakes, no doubt descendants of land-snakes, which show a 
posterior flattening of the body from side to side, giving them 
a good grip of the water when they swim. At least some of 
them come to the shore to bring forth their young. 


Fishes in the Open Sea 

There are many Open-sea fishes like the so-called Flying 
Fishes, which skim along the waves when pursued by the Tunny, 
or may take advantage of a breeze to “sail” like an albatross. 
Mackerel and herring might be counted also as characteristically 
pelagic fishes. Among backboneless animals there are many 


Photo: The Holloway Studio, Ltd. 
AN ICEBERG 


Icebergs are the detached sea-ends of coastal glaciers. Some are several miles inlength and many are very high. Asthesubmerged 
part gradually meltsaway they turnturtle. They are glittering white in the sun, often pearl-grey in the shade and rich blue in their clefts. 
‘‘ Their stupendous size, their exquisite architectural composition, more magnificent than the temples and pyramids of Egypt, more 
Overpowering in solemnity than the Sphinx—make the most thoughtless think for a moment of the Power that controls the forces of 
nature’’ (W.S. Bruce, of the Scotia). 


’ A CORAL FISH 


One of the most beautiful of the inhabitants of the coral-reef, 
resplendent with blues and gold and green. 


Reproduced by courtesy of 
Messrs. Andrew Melrose, 
Ltd., from ‘‘The Haunts of 
Life’’ by Professor J. 
Arthur Thomson. 


A FLOATING 
BARNACLE 


After the youthful free- 
swimming stage is over, 
the barnacle attaches itself 
to a piece of floating sea- 
weed or the like. If 
growth makes it too heavy 
to be kept afloat by the 
support, it makes a buoy 
(shown on the stalk por- 
tion in the figure) to re- 
store the balance. 


Reproduced by courtesy of Messrs. Andrew Melrose, Ltd., from ‘‘The Haunis of Life’’ 
by Professor 7. Arthur Thomson. 


THE FLOOR OF THE DEEP SEA 


Showing a dredge being dragged along, a long-legged crustacean (foreground), 
three strange abyssal fishes, and (extreme left) a graceful yard-high Umbellula, 
with a tassel of Polyps at the top and the base fixed in the ooze. (For the 
characteristics of deep-sea animals see text.) 


The Science of the Sea 981 


that frequent the open waters—the beautiful sea-snails or sea- 
butterflies which whalebone whales are fond of, the argonaut 
cuttlefish which has the most beautiful cradle in the world 
(see figure facing p. 117), hundreds and hundreds of different 
kinds of crustaceans, one family of pelagic insects, various trans- 
parent worms, the exquisite Ctenophores, the strange Portuguese 
Man-of-War, the jellyfishes and the swimming-bells, and many 
Protozoa—often extraordinarily beautiful like the calcareous 
Globigerinids and the siliceous Radiolaria. Some are active swim- 
mers, some are easy-going drifters, and one must remember that 
besides the animals that live always in the open waters there are 
many larve which only spend their youth there, afterwards return- 

ing to the more strenuous life of the shore. Among Open-sea 
animals there are endless adaptations that secure floatability, 
that save them from being broken by the waves, that help them 
to get their food, and that give the young ones a successful start; 
but let us take one instance. Ordinary ship-barnacles hatch 
out as minute free-swimming larve; after a while they fix them- 
selves to floating logs or wooden ships, and the front of the 
head grows into a long flexible stalk, at the end of which there 
dangles the crustacean’s main body. It is encased in five valves 
of lime, and six pairs of beautifully curled feet waft the food 
into the mouth. So far the common barnacle, but there is an- 
other species (Lepas fascicularis) which has a different history. 


It often fastens itself to a small piece of detached seaweed 
—it may be a feather or a wooden match. Its shell-valves 
are very lightly built, with little lime in them, and this is 
well suited for a creature that fixes itself to a light float. 
But in spite of its lightness of shell, the Floating Barnacle, 
as we may call it, often becomes, as it grows bigger, too 
heavy for its float, and begins to drag it below the surface. 
What, then, does the creature do—we wish we understood 
it better—but make a somewhat gelatinous, roundish buoy 
containing bubbles of gas. ‘This is secreted at the lower 
end of the attaching stalk, just above the main body, and 


982 The Outline of Science 


the self-made buoy enables the barnacle to continue floating 
at the surface. This is a beautiful adaptation.* 


Deep-sea Animals 

No doubt the strangest haunt of life is the Deep Sea, by 
which is meant the floor of the very deep parts of the sea and 
the layers of dark water near the floor. It may be six miles 
below the surface; there is enormous pressure because of the 
immense weight of water—214 tons on the square inch at 2,500 
fathoms; it is very cold—a little on each side of the freezing- 
point of fresh water; it is absolutely dark apart from the fitful 
gleams of luminescent animals; it is calm, silent, monotonous, 
and plantless. But there is no “deep” too deep for animal life; 
indeed, in many places there is an abundant abyssal fauna. 
Some of the adaptations to the strange haunt are readily in- 
telligible. The long stalks of sea-lilies and sea-pens lift the 
body out of the treacherous ooze; the long legs of some crabs 
and sea-spiders are suited for walking delicately; there is often 
an exquisite development of tactility well fitted for a world of 
darkness; the body is often porous and so thoroughly pene- 
trated by water that the great pressure is not felt. Perhaps the 
big goggle eyes of some of the nightmare-like abyssal fishes may 
be suited for utilising the phosphorescent light. Some Deep-sea 
animals, whose seashore relatives liberate eggs, bring forth 
young ones viviparously—probably an adaptation that counter- 
acts the risk of the passive eggs being smothered in the ooze. 

As there are no plants in the abysses, the struggle for 
existence among the larger animals must be keen, and the teeth 
of many of the Deep-sea fishes declare their fiercely carnivorous 
habits. We can understand why the gape of some of these 
fishes is often so large in proportion to the body; they must 
make the most of a meal when they get a chance. The stomach 


is sometimes very elastic and the under surface of the body very 
*Thomson, Haunts of Life, 1921. 


The Science of the Sea 983 


dilatable, so that what is swallowed may be large—even too 
large—for the size of the body. When a big Open-sea animal, 
like a whale, comes to grief and sinks to the bottom, with its 
flesh much compacted by the driving out of water from the 
muscle-fibres, it will be nibbled to bits by legions of crustaceans, 
such as some of the sea-slaters or Isopods, for it is not known 
that there is any rotting in the Deep Sea. But what counts for 
most in the way of nutrition is not the sinking down of big things, 
it is the rain of dead animalcules from the surface miles over- 
head. The circulation of matter is doubtless illustrated in the 
Deep Sea just as elsewhere: the fish eats the crustacean, and 
that the worm, and that the organic particles of the ooze; but it 
is possible that the vital processes are slowed down considerably 
in the conditions of great pressure, low temperature, and eternal 
night, so that the severity of the rationing is not so much felt 
as we might expect. The delicate bones and soft flesh of some of 
the abyssal fishes suggest that they are not capable of very ener- 
getic movements. And that would make the food-problem easier. 

Can we make any sort of picture of a Deep-sea scene? 
Darkness like that of a moor at midnight with no light except 
from stars and will-o’-the-wisps. Beds of sea-pens with their 
bases in the ooze, swayed gently by their own life, like rocking 
lighthouses; many other long-stalked creatures, often supremely 
graceful, the sea-lilies for instance. Now and then among the 
fixed forms there come ruddy crustaceans, stealthily prowling, 
some with long limbs like stilts and with far-reaching feelers 
that probe into distant corners. Then there are cuttlefishes and 
true fishes, mostly swimming slowly, and often lit up all over 


like ocean liners at supper-time. 


§ 8 
Seashore Animals 
In the Natural History sense the shore-area means the 
whole stretch of well-lighted, relatively shallow water, where 


984 The Outline of Science 


seaweeds grow. As a haunt it is marked by notable diversity, 
much changefulness, great congestion, and a keen struggle for 
existence—struggle for foothold and for food, against furious 
storms, and the appetite of many enemies. 

Almost every kind of animal is represented on the littoral 
area; there are even some seashore insects and spiders. ‘Thus it 
seems fair to speak of seals as shore mammals, since they come on 
to dry land not only at the breeding season but for resting pur- 
poses at any time. It is plain that their emancipation from dry 
land is less thoroughgoing than that of whales, but yet their 
adaptations are many. ‘The somewhat conical shape is suited 
for swift swimming; everything is done to reduce friction; the 
hind-legs are thrown backwards beside the short tail to form 
a propeller. The nostrils can be closed under water; the sensi- 
tive whisker hairs are of use in dark diving; the structure of the 
eye is adjusted to the gloom. ‘The blubber makes the seal buoy- 
ant, it shuts in the animal heat, it is a store to fall back on when 
it is too stormy to fish. The teeth, with their tips tilted back- 
wards, serve to grip the slippery booty. What a bundle of 
fitnesses! 

The common Seal (Phoca vitulina) can swim at the rate 
of ten miles an hour, which is about half the dolphin’s speed. The 
fore-limbs are kept close to the breast, except when turning or 
steering; the swimming is due to the very muscular posterior 
body, aided by the hind-legs—a powerful propeller that does not 
turn round! ‘The movements on land are rather toilsome. Seals 
are quick of hearing and gather to unusual sounds, such as music. 
They have fine brains, affectionate dispositions, and a pleasant 
playfulness. In their conjugal relations they are at once poly- 
gamus and polyandrous. ‘The pup can take to the water the day 
of its birth, but it needs long rests ashore and much mothering, 
which it certainly gets. 

The Polar Bear of the Far North is a seashore animal, and 
often lies on the ice waiting for a seal’s head to bob up. One of 


The Science of the Sea 985 


the Arctic Explorers has told us of a Polar Bear lifting the seal 
right out of the water with one stroke of the arm, and sending it 
crashing over the ice with its skull stove in. The walruses, also 
of the North, dig up shore bivalves with their huge tusks. Those 
archaic mammals, the dugong and the manatee, are also littoral, 
and it is interesting to hear of the manatee finding its way far 
inland to that naturalist’s paradise, the Everglades of Florida, 
thus becoming practically a freshwater mammal. 

Many birds frequent the shore, but in most cases for a season 
only. We think of gulls and terns and cormorants, of sandpipers 
and curlews and oyster-catchers—the last able to knock the 
limpets off the rocks with dexterous strokes of their bills. The 
seaweed-eating edible turtles can never go far from the shore, and 
there is a marine lizard (Amblyrhynchus) of the Galapagos 
Islands that swims out to sea and dives among the seaweed. 

The seashore fishes are many—e.g. fatherlasher, sand-eel, 
cock-paidle, and stickleback. Very characteristic is the Gunnel 
or Butterfish (Centronotus gunnellus), which is incredibly diffi- 
cult to catch because of its powers of insinuating itself between the 
stones and into crevices, and of slipping through your fingers 
when you have captured it at last. Many of the sea-squirts, which 
start life as Vertebrates and end as degenerate nondescripts are at 
home on the shore. And in the clean sand out a few yards there 
is often some kind of Balanoglossus—a most interesting connect- 
ing link (vulgarly supposed to be always “missing’’) between 
worms and Vertebrates. 

Of littoral molluscs there seems at first no end—the tooth- 
some vegetarian periwinkles, the limpets clinging to the rocks and 
“homing” from a short distance, the carnivorous “roaring 
buckies” or big whelks whose shells children hold to their ears like 
portable “whispering galleries,” and the dog-whelks everywhere. 
Cockles and mussels, oysters and clams, scallops and razor-shells, 
are familiar bivalves of the shore-area, feeding daintily on micro- 
scopic organisms and organic particles which the gills waft into 


986 The Outline of Science 


the mouth. The Octopuses lurking among the rocks on the look- 
out for crabs are the highest of Invertebrates, and are occasionally 
big enough to be formidable to man as Victor Hugo portrays in 
his immortal Tilers of the Sea. 

Shore crustaceans are legion—crabs and lobsters, shrimps and 
prawns, Amphipods and Isopods, acorn-shells and water-fleas. 
What combinations of armour and weapons; what camouflaging 
and trickery; what fitnesses they show! A common accident is 
the bruising of a crab’s leg by a dislodged stone; it will not 
mend, so it is sacrificed; and under the bandage, where the self- 
mutilation is effected, a new leg is formed in miniature. ‘Then 
there is such a “living fossil” as the King Crab of North Ameri- 
can coasts and the Moluccas, the last of an ancient race, a Rip 
Van Winkle among Arthropods, breathing by “gill-books” which 
no other animal in the world possesses. Its type has been living 
on since the Triassic—for millions of years; and it is fed to pigs! 

There are also starfishes and brittle-stars, sea-urchins and 
sea-cucumbers, many of them practising the same reflex device 
as the crabs—a limb for a life: autotomy is followed by regene- 
ration, as the technical phraseology quaintly puts it. Of the 
legions of worms, wandering and sedentary, segmented and 
unsegmented, no outsider can form a picture, but everyone 
knows the lob-worm or lug-worm which the fishermen dig for 
bait. It does on the flat beach what the earthworm does in the 
meadow: it keeps the soil circulating. Lower still are the corals 
and sea-anemones, the zoophytes and shore sponges, and the 
microscopic Foraminifera and Infusorians. Perhaps there is 
no haunt of life so interesting as the shore. It is so varied in 
different places, so diverse at the same place, so changeful, so 
stimulating, so full of danger. Given a diversified, changeful, 
difficult haunt, densely peopled by a representative set of 
animals, there must be a keen struggle for existence and a cease- 
less sifting. Given a very stimulating environment, as the shore 
is par excellence, there will be opportunity to test all the varia- 


The Science of the Sea 987 


tions which living creatures are ever venturing. It may be, 
indeed, that the stimulating character of the seashore has been, 
through the ages, provocative of those new departures which 
form the raw materials of evolution. The shore is a treasure- 
all sorts of answers-back to the limitations 


house of adaptations 
and difficulties which meet the “urges” of “hunger” and “love.” 
Most of the great stocks of animals have passed through the 
discipline of the shore-school, and even in man we can hear the 
echoes of the ancient tides. 


BIBLIOGRAPHY 


CHALLENGER Society, The Science of the Sea (London, 1912). 

HerrvsBeE., Sea Fisheries (London, 1912). 

JounstTone, Life in the Sea (Cambridge Manuals, 1911); also The Conditions 
of Life in the Sea. 

Mixu, H. R., The Realm of Nature (University Extension Series). 

Murray anp Hyort, The Depths of the Sea (London, 1912). 

Murray, Sir Joun, The Ocean (Home University Library). 


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XXX 


ELECTRIC AND LUMINOUS ORGANISMS 


989 


ELECTRIC AND LUMINOUS ORGANISMS 


NERGY, as we have seen in a previous chapter, is the 
power of doing work, or of changing the state of motion 
of a body. It takes many forms, such as heat, light, 

electricity, energy of movement, energy of position, and chem- 
ical energy. These are transformable into one another and they 
are transferable from one body to another body, but no energy 
is ever lost. The energy of the burning coal may drive a dynamo 
which generates electricity which lights a street, but 


however much energy may be transformed or transferred, 
when any quantity of one form disappears a precisely equal 
quantity simultaneously appears in some other form or 
forms. Just as with matter, you cannot create or destroy 
any quantity of energy, however small, and since energy 
is the great worker of the universe you cannot get some- 
thing for nothing. 


This is the generai idea of “the conservation of energy,” which 
must be borne in mind in thinking about those animals, like the 
Electric Eel, that can give an electric shock, and those animals 
and plants that can produce a brilliant light, like fire-flies and 
some bacteria. No living creature produces any new energy; 
all that can be done is to change one form of energy into another. 


§ 1 


Luminous Plants 


It is well known that fishes hung up to dry are often 


brightly luminous in the dark. The same appearance is often 
991 


992 The Outline of Science 


seen on dead flesh, and it has been familiar since the time of 
Aristotle. But the discovery of the cause of the light is modern. 
It is due to some kind of bacterium, which is living very intensely 
on the fish or flesh, and is giving forth light as a by-product of 
its activity. The chemical energy of the bacteria is being changed 
into light energy. About thirty different kinds of luminous 
bacteria are known, one of the commonest being Bactertwm phos- 
phorewm. 'They occur in a great variety of situations, including 
wounds on the human body, and have often given rise to super- 
stitious interpretations. 

Apart from bacteria, there is light-production in some of 
the moulds and other fungi. Thus in the South of Europe there 
is a well-known luminous toadstool (Agaricus olearius) that 
grows at the foot of olive-trees, and there are many other cases. 
In some forms the light is produced only by the fine threads 
(mycelium) of the fungus; in others the whole of the disc of the 
toadstool shines. ‘The luminosity of rotting wood, which inter- 
ested Aristotle, is due to the spreading threads of a fungus, and 
some roots, e.g. those of the Common Tormentil (Potentilla 
tormentilla) of our hill-pastures, are likewise penetrated by 
shining filaments. The same explanation applies to the decay- 
ing leaves of beech and oak, which may sometimes be seen 
glimmering on the ground in the darkness. Small yellowish- 
white spots on the underside of the beech-leaves mark the head- 
quarters of the microscopic threads of a luminous fungus. In 
decaying wood and leaves the light is due to fungoid threads, 
not to bacteria; but great care must be taken to make sure that 
the luminescence in any particular instance is due to the fungus 
and not to some associated bacteria. For, as a separate article 
makes clear, bacteria have a finger in many a pie. It is time to 
drop the word “phosphorescence” altogether in reference to 
living lights, for they have nothing to do with phosphorus. 

In dim recesses among the rocks there lives the so-called 
“Tuminous moss,” but its gleaming is merely the reflection of the 


Electric and Luminous Organisms 993 


sparse rays of daylight from reflecting surfaces of somewhat lens- 
like skin-cells. The lens-like structure is an adaptation to make 
the most of the little light that is going, for light is every- 
thing to a green plant. The shining appearance that suggests 
light-production is, so to speak, an incidental phenomenon, 
meaning no more than the shining of the cat’s eyes in the dark. 
For these cat’s eyes have, we feel assured, no power of producing 
light; they are merely light-reflecting. This is due to a strongly 
developed mirror-like layer (tapetum) at the back of the cat’s 
eye, the significance of which is not to make the eye “shine in the 
dark,” but to enable the cat to make the most of the little light 
there is available during its nocturnal hunting. 

Among the other cases of apparent light-production we 
must refer to the beautiful sight that we often see in looking 
down into a shore-pool. The seaweeds show fascinating chang- 
ing lights as they are gently swayed by the tide. Brown changes 
into blue, and blue into gold. ‘This is a physical phenomenon, 
difficult to analyse, but it has nothing to do with light-produc- 
tion. ‘Two kinds of phenomena are involved. There is a certain 
amount of iridescence due to the physical structure of the surface 
of the seaweed, just as in a peacock’s feather. But there is also 
a “fluorescence,” depending on deeper properties of the contents 
of the cells. | 

As to the moving lights or “will-o’-the-wisps” sometimes 
seen in marshy places, they are probably due to the combustion 
of marsh gas or of phosphene, but the question has not been 
satisfactorily answered. St. Elmo’s fire, which sailors sometimes 
see at the mast-head, is caused by a brush-like discharge of 
electricity from a low cloud. 


§ 2 
Luminous Animals 
The production of light by animals is a phenomenon which 
occurs more widely than is generally realised. It is known in no 


VOL. IV—9 


994 The Outline of Science 


fewer than thirty-six orders of animals, and there does not seem 
much rhyme or reason in its distribution. It is seen in various 
Infusorians like Noctiluca, the Night-light, which makes the sea 
sparkle in the short summer darkness; in numerous Stinging 
Animals, like the fixed Sea-Pens and the Portuguese Men-of- 
War of the open sea; in sundry marine worms; in starfishes and 
brittle-stars; in many crustaceans and insects; in some squids 
and in two or three molluscs; in compound Ascidians, like the 
Fire-flame (Pyrosoma), by whose light one can see to read; and 
in many fishes, especially from the deep sea. Animal lumi- 
nescence does not occur above the level of fishes, for a “luminous” 
frog turned out to have dined well on fire-flies, and persistent 
reports of certain luminous birds, e.g. herons, are probably based 
on inexpert observation or on some fouling of the bird’s feathers 
with luminous bacteria or fungi. There have been records of 
luminescence in a few freshwater animals, e.g. in the larve of 
one of the harlequin-flies, ‘but it is usually maintained that 
“animal lights” occur only in the sea and on dry land. 

What is the nature of this animal light? Robert Boyle 
proved in 1667 that air is necessary for the luminescence of 
decaying wood and dead fishes. ‘This implies that what occurs 
is of the nature of an oxidation or combustion. In 1794 the not 
less ingenious Italian naturalist Spallanzani showed that when 
dried. parts of luminous jelly-fishes are re-moistened they will 
emit light as before. This implies that what occurs is not in the 
strict sense vital. It is a chemical process. But it is possible 
to go further. 

About 1887 Raphael Dubois, a French zoologist, made a 
very interesting experiment with a luminous bivalve, called 
Pholas, which bores holes in the seashore rocks. He made a 
hot-water and a cold-water extract of the luminous tissue of the 
mollusc, and let them stand till the light disappeared in both. 
He then mixed the two together, and there was luminescence 
again! ‘This led him to the theory that a ferment-like substance, 


A DEEP-SEA SCENE (mostly after Chun) 


1. A deep-sea prawn with remarkably elongated feelers and legs. 2. A giant sea-pen, Anthoptilum, with its base embedded in the 
ooze. This is shown separately on page 1002. Tothe right of Anthoptilum is seen a graceful relative called Umbellula with the tuft 
of polyps on a long flexible stalk. 3. A small deep-sea fish (Melanocetus) with a luminous organ on the end of a stelk. 4. Young 
form of a deep-sea fish (Stylophthalmus) from the Indian Ocean, with the eyes on long stalks. 5. An abyssal fish with a prolonged 
snout region. 6. A beautiful sea-lily or crinoid, with fixed base, and ten feathery arms at the top of the long stalk. 7. Another 
deep-sea fish with numerous luminescent organs. 8. A small cuttlefish, Lycoteuthis diadema, about natural size, with regularly 
arranged luminous organs. 


A REMARKABLE LUMINOUS FISH, Lamprotoxu flagellibarba, FROM DEEP WATER OFF THE SOUTH-WEST OF 
IRELAND. (After Holt and Byrne) 


It is about seven inches long. The small spots and the looped band are luminous. Very remarkable is the long tactile 
barbel. Its coiling below the body is unnatural. It probably projects in front, several times longer than the fish, a feeler in 
the dark water. 


Electric and Luminous Organisms 995 


destroyed by heating, and absent therefore in the hot-water 
extract, produces light when it operates on another substance 
which is oxidised. In the cold-water extract the light-producing 
substance had been used up by the ferment; in the hot-water 
extract the ferment had been destroyed, but the oxidisable 
material was still present. Therefore a mixture of the two 
extracts resulted in the production of light for a while. 

The experiments of Professor Dubois have been confirmed 
and extended by Professor Newton Harvey, and the theory 
works well in regard to the three cases of animal luminescence 
that have been most studied, namely, the boring bivalve, a small 
marine crustacean called Cypridina, and those luminous beetles 
which are properly called fire-flies. The theory may be stated 
thus. Luminescence occurs in the presence of oxygen and 
water, and is due to the interaction of two different substances. 
One of these, the luciferase, acts like a ferment on the other, 
luciferin, and oxidises it or accelerates its oxidation, with the 
result that light is produced, as in some other rapid chemical 
processes. 


Faraday’s Contribution 

The history of the scientific solution of a problem is 1arely 
simple, and we know we are leaving out some important investi- 
gations and investigators when we say that the great steps in 
the still partial elucidation of the problem are: 

(1) When Robert Boyle showed that luminescence was de- 
pendent on the presence of oxygen; 

(41) When Spallanzani showed that luminescence was 
independent of the life of the animal; and 

(iii) When Raphael Dubois made it almost certain that 
in Pholas there is a co-operation of a ferment-like substance 
with a potentially luminous substance—a view confirmed by 
Professor Newton Harvey. 

But, however short our history, we cannot omit reference 


996 The Outline of Science 


to the experiments of Faraday, who was extraordinarily inter- 
ested in the luminescence of glow-worms (in 1814!) and made 
many experiments. His genius was evident in his endeavour 
“to ascertain whether the luminous appearance depended on the 
life of the fly,” in his observation that “no heat was sensible to 
the hands or to the underlip—the most delicate part of the body.” 
His conclusions were (a) that there is a chemical:substance in 
the glow-worm which has power to shine independently of the 
life of the insect; (b) that the luminous substance is probably 
a secretion of the insect; (c) that the shining depends on air; 
and (d) that the luminescence as a whole is controlled by the 
creature in the ordinary conditions of its manifestations. 


3 

The Nature of Animal Light 

A body that gives off light-rays because of its high temper- 
ature is said to be incandescent. But when the emission of light 
is due to some other cause we use the term lwminescent. All 
animal light is “cold light,” for not only is it produced apart 
from high temperature, but it is all light without any heat. Thus 
the luminescence of the fire-fly has been called “the cheapest 
form of light,” for none of the energy is lost in the form of heat, 
and it would be great gain if man could learn the fire-fly’s 
method. Moreover, the animal light is all visible light; it has 
no infra-red or ultra-violet rays. Yet it behaves in general like 
ordinary light—it affects a photographic plate; it can produce 
phosphorescence and fluorescence in various substances; it causes 
plant seedlings to bend towards it; and it stimulates the forma- 
tion of chlorophyll. 


The Fire-fly’s Light Excels all Human Devices 


It is interesting to quote a sentence from the paper in which 
Professor S. P. Langley and Mr. F. W. Very proved that the 
luminescence of the fire-fly is “the cheapest form of light,” mean- 


From Professor Doflein. 


LUMINOUS DEEP-SEA Al AL THE MID-ATLANTIC 


The production of light by < is a phenomenon S n e: y in species from the deep sea. 


ustration shows striking examples: a prawn (Acanthephyra); a cuttle-fish (Thaumatolampas); a fish (Gono- 


stoma) pursuing othe 


Electric and Luminous Organisms 997 


ing by this phrase that in the transformation of energy which 
results in the insect’s glow there is greater economy than in any 
other known transformation that results in light. 


Resuming, then, what we have said, we repeat that nature 
produces this cheapest light at about one four-hundredth 
part of the cost of the energy which is expended in the 
candle-flame, and at but an insignificant fraction of the 
cost of the electric light or the most economic light which 
has yet been devised [this was in 1890]; and that, finally, 
there seems to be no reason why we are forbidden to hope 
that we may yet discover a method (since such a one cer- 
tainly exists and is in use on a small scale) of obtaining 
an enormously greater result than we now do from our 
present ordinary means of producing light. 


Different Colours of Animal Light 

A little must be said in regard to the different colours of 
“animal light,” though we are unable to make any suggestion 
as to their significance, especially as they may be red, blue, and 
green in one and the same animal at different times. Green is 
illustrated by the glow-worm and some brittle-stars; blue by 
the Italian fire-fly; red by the Girdle of Venus and some Salps; 
and lilac by some Alcyonarian corals. In general it may be said 
that in marine luminescent animals the commonest colours are 
blue and light green. A purple light has been ascribed to the 
swollen proboscis of the Lantern-fly (Fulgora), but this insect 
is not really luminescent. 


Different Modes of Light-Production 

The animal light may be produced only in situ in certain 
cells where the luminous substance is produced, as in the Night- 
light of the sea or the glow-worm in its “dell of dew.” Or there 
may be a luminous secretion that exudes over the surface of 
the body and spreads into the sea or forms a trail on the ground. 
This is seen very clearly in some small crustaceans (Copepods), 


998 The Outline of Science 


where the light is not visible until there is actual exudation of 
the light-producing substance or substances. 

In many cases, however, as in some fishes, some cuttlefishes, 
and some higher crustaceans, the light streams out from elabo- 
rate luminous organs, and the remarkable thing is that these are 
often like eyes. In front of the light-producing cells there may 
be a lens, sometimes triple. Behind them there may be a 
reflector. Round the sides of the organ and behind the reflector 
there is often a dark envelope shutting off the light from the 
tissues of the animal itself. And then there is a stimulating and 
controlling nerve. Now this is all very suggestive of an eye, 
which has its lens, its reflector (we think of the cat’s eye shining 
in the dark), and its darkly pigmented envelope which makes a 
camera. In the luminous organ, as Professor Newton Harvey 
neatly says, the important transformation of energy is chemi- 
photic (from chemical changes to light), while in the eye it is 
photo-chemical (from light to chemical processes). Of course 
the nerve of the luminous organ is of the stimulating or control- 
ling sort, carrying a message out, while the nerve of the eye is 
sensory or afferent, carrying messages in to the brain. It seems 
important to emphasise the resemblance between an eye and a 
luminous organ, for in the eye there is a direct conversion of 
light energy into chemical processes, just as in the laboratory 
of the green leaf. And what is most remarkable in luminous 
living creatures is the direct conversion of chemical energy into 
light, and that without passing through heat, and quite apart 
from the application of heat. 


When the Dredge Comes Up 


The Marquis de Folin, who led one of the French deep-sea 
expeditions, describes the surprise and delight of the naturalists 
on board the exploring vessel when they first saw the dredge 
brought up in the darkness from a great abyss. There were 
many coral animals, shrub-like in form, which threw off 


A VIEW IN A SURREY LANE, WITH THE HEDGE-BANKS LIT UP BY GLOW-WORMS 
THAT HAVE CLIMBED THE HERBAGE 


In some favoured places they are specially abundant. The glow-worm (Lampyris noctiluca) 
belongs to the order of beetles, and the European fire-flies are closely allied. 


THE ELECTRIC CAT-FISH 


Its capacity for producing shocks is only slightly inferior to that of the Electric Eel. Its battery envelops the whole body 
between the skin and the muscles, and is itself a transformation of the skin. 


a & = + 
ents »*% 


etasnevas« ** ** Sey * 9S * »* bal = ba 
< ; 


TWO DEEP-SEA FISHES (FROM THE PRINCE OF MONACO’S MEMOIRS) 


The upper one, Gonostoma polyphos, is about 10 inches long, dense black, without scales, and with numerous luminous organs in- 
dicated by the white spots. The upper row of lateral luminous organs are green, blue, and violet; the lower row red and orange; those 
at the root of the tail red; and there are some violet ones along the ventral surface. The lower fish, Photostomias guernei, is smaller, 


though drawn to the same size. Its surface is velvety black and there are 1,500luminous organs. The far-back hinging of the lower 
jaw gives the fish an extraordinary gape. 


A FIRE-FLY 


A beetle of tropical America with luminous patches on both 
upper and under sides. The upper patches are shown in 
white. The figure is twice the actuallength. It would seem, 
in the case of some fire-flies, that flashes of light from the one 
sex to the other play some part in the mating. 


Electric and Luminous Organisms 999 


flashes of light beside which the twenty torches used for 
working by were pale. Some of these corals were carried 
into the laboratory, where the lights were put out. There 
was a moment of magic, the most marvellous spectacle that 
was given to man to admire. Every point of the chief 
branches and twigs of the coral Isis threw out brilliant jets 
of fire, now paling, now reviving again, to pass from violet 
to purple, from red to orange, from bluish to different tones 
of green, and sometimes to the white of over-heated iron. 
The pervading colour was greenish, the others appeared 
only in transient flashes, and melted into the green again. 
Minute by minute the glory lessened, as the animals died, 
and at the end of a quarter of an hour they were all like 
dead and withered branches. But while they were at their 
best one could read by their light the finest print of a news- 
paper at a distance of six yards. 


In the corals the luminescence was diffuse, in other cases it was 
localised in organs. ‘Thus one of the cuttlefishes had about 
twenty luminous spots, “like gleaming jewels, ultra-marine, 
ruby-red, sky-blue, and silvery.” 


The Illumination of the Sea 

In Huxley’s account of his voyage in the Rattlesnake there 
is a fine description of the illumination of the sea by the “pillars 
of fire” called Pyrosomes. 


The sky was clear but moonless, and the sea calm; and a 
more beautiful sight can hardly be imagined than that 
presented from the deck of the ship as she drifted, hour 
after hour, through this shoal of miniature pillars of fire 
gleaming out of the dark sea, with an ever-waning, ever- 
brightening, soft bluish light, as far as the eye could reach 
on every side. 

The Fire-Flames floated deep, and it was only with 
difficulty that some were procured for examination and 
placed in a bucketful of sea-water. The phosphorescence 
was intermittent, periods of darkness alternating with 


1000 The Outline of Science 


periods of brilliancy. The light commenced at one 
point, apparently on the surface of one of the members of 
the Fire-Flame colony, and gradually spread from this 
centre in all directions; then the whole was lighted up; it 
remained brilliant for a few seconds, and then gradually 
faded and died away, until the whole colony was dark again. 
Friction at any point induces the light at that point, and 
from thence the phosphorescence spreads over the whole, 
while the creature is quite freshly taken; afterwards, the 
illumination arising from the friction is only local. 


§ 4 


Possible Uses of Animal Lights 

When a living creature simply exudes a luminous secretion, 
or glows as it oxidises certain complex substances in various 
parts of its body, it is quite possible that the luminescence is 
not as such of any importance in the everyday life of the crea- 
ture. It may be no more than the by-play of something more 
vital, a side-track in the metabolism of the body. Thus no one 
feels bound to search for a use of the luminescence of certain 
bacteria or of the eggs of fire-flies. But the case is quite differ- 
ent when an elaborate luminous organ has been evolved. Then 
there must be a use. But most of the suggestions in the field 
are highly speculative. 

(1) In some cases the luminescence may possibly serve to 
scare away intruders, or, if it is intermittent, to distract preda- 
tory animals. Perhaps a sea-pen suddenly illumined may warn 
off intruders. (2) In some cases the light may be a lure attract- 
ing booty in the darkness of deep waters, and it is striking that 
the luminous organ of an abyssal fish is sometimes pendent on 
a tentacle hanging down in front of the mouth. (3) In other 
cases the light may serve as a lantern, enabling deep-sea squids 
and fishes, for instance, to find their way about in the darkness. 
But this interpretation is only applicable when the hypothetical 


Electric and Luminous Organisms 1001 


lantern is hung in an appropriate place, which is far from being 
generally true. (4) In many cases the luminous organs have a 
very definite pattern, e.g. on the sides of the body of the fish. In 
the dark waters this pattern may facilitate the recognition of kin 
by kin. (5) In some cases the facts certainly suggest that the 
light is used as a sex-signal. It is noteworthy that the toad-fish, 
Porichthys, is luminous only during the breeding season. In the 
glow-worm, the female of the British species, Lampyris noc- 
tiluca, is wingless and creeps on grassy banks. She is more 
luminous than the male beetle, which flies about overhead. The 
intermittent luminous glow streams forth from two strata of 
cells, well-provided with air-tubes, near the posterior end of the 
body of the adult; but it is also seen in the larve and on the eggs. 

The fire-flies are beetles related to our glow-worms, and 
the crowds of shining males dancing in the air in the summer 
twilight are familiar and beautful sights in warm countries. In 
the case of the Italian fire-fly, Luciola italica, the female is a 
small-eyed, weak-legged creature compared with the male, but 
she has wings and luminescence. She is very rarely seen except 
when she attracts round about her on the ground a brilliant circle 
of ardent suitors. It seems to the human spectator that flashes 
of light from the one sex to the other play some part in the 
mating. But there is no certainty. In the meadows around 
Bologna the female fire-fly may sometimes be seen in the evening 
among the grass. Numerous males fly about overhead. It 
looks as if the approach of a male served as the stimulus to the 
female to let her light shine forth. It looks as if he saw her 
signal—these things are difficult to prove—at any rate, he is 
soon beside her, circling round like a dancing elf. But one suitor 
is not enough. The female attracts a levée. Her suitors form 
a circle around her on the ground, and flashes pass to and fro. 
The luminous rhythm of the males is more rapid, with briefer 
flashes; while that of the female is more prolonged, but with 
longer intervals. 


1002 The Outline of Science 


In a large Ceylonese glow-worm or fire-fly (Lamprophorus 
tenebrosus), the larve are luminous as well as the winged male 
and wingless female, and the colour of the light is emerald green. 
The female seems to signal to the male but a curious point is 
that the male often shuts off his hight when approaching a 
“calling” female. 


a 


ANIMAL HEAT 


If a thermomeier is inserted into a beehive it shows a rise 
of temperature. Where is the heat coming from? The answer 
must be that the movements of the muscles of the hundreds of 
bees are producing heat which raises the temperature of the air 
in the hive. The chief source of animal heat is to be found in 
the activity of the muscles. 

On a very cold day one sees cabmen beating their arms on 
their body in order to keep warm. They are quickening the circu- 
lation by exercise but they are also making the muscle-engines 
work rapidly, so that much heat is produced. The bee is a cold- 
blooded animal, i.e. of changeful temperature tending to ap- 
proach that of the surroundings. The heat produced by the bees 
passes out into the air, and would be wasted in winter were not 
the hive a confined space. But the cabman is warm-blooded, 
i.e. of constant temperature, and in very cold weather he is able 
to adjust his body-temperature to the circumstances by increas- 
ing the internal production of heat and still more by lessening 
the loss from the skin. For the cold brings about a constriction 
of the blood-vessels in the skin, less heat is lost, and the man 
“looks cold.” Conversely, on a very hot day a dog increases its 
loss of heat by putting out its tongue. Only in birds and 
mammals is there this power of regulating production and loss 
of heat, which is called “warm-bloodedness.” ‘The nerve-centre 
for its regulation is in the corpus striatum of the brain. It may 


A MAGNIFICENT LUMINOUS SEA-PEN (ANTHOPTILUM), ABOUT A YARD HIGH, FROM DEEP WATER OFF JAPAN 


The swollen base is embedded in the ooze, and the stem sways in the water as suggested in Fig. 2 of theillustration on page 994. 


The twist shown in the figure is not natural. Very striking are the hundreds of large polyps composing the colony: each is about 
an inch long. 


A SMALL ELECTRIC RAY, Zorpedo ocellata, FROM THE 
MEDITERRANEAN, SHOWING THE DORSAL SURFACE 


The position of the large Electric Organ (E.O.) is between 
the brain and the front of the large pectoral fin. Behind the 
eyes are seen two breathing holes or spiracles (.S.P.), by which 
water passes to the gills. The gill-clefts by which the water 
passes out are on the ventral surface. There are curious pig- 
ment spots (P.S.), like eyes, on the dorsal surface. 


TWO ELECTRIC FISHES 


1. The Electric Eel: Gymnotus. The shocks pass, as the arrow indicates, from the tail towards 
the head. About four-fifths of its length is tail; on each side of this there lies a huge electric organ. 
The strength of the electric shock is sometimes sufficient to stun a man or to kill the fish’s prey. 

2. The Electric Catfish: Malopterurus. The shocks pass, as the arrow indicates, from the head 
towards the tail. 


Electric and Luminous Organisms 1003 


be noted that shivering is an irregular kind of contraction 
brought about by commands coming from the nervous system 
to the muscles, ordering the production of more heat. 

All living involves oxidations or combustions, and some of 
the animal heat is due to the chemical processes which go on cease- 
lessly thoughout the body. But these account for only a small 
fraction of the total amount. In the main the animal heat comes 
from the muscles, and it is important to notice that they produce 
heat even when the body is at rest. This happens, for instance, 
when we are asleep, when there are not many muscles actually 
working except those of the heart and those concerned in breath- 
ing movements. The amount of heat produced during sleep is 
not so great as during waking hours, and everyone knows how 
cold a sleeper becomes in winter if he has not enough of blankets, 
how dangerous it is to fall asleep in the snow, and how animals 
take precautions of many kinds to secure comfortable resting- 
places. 

In the contraction of a muscle there are two chapters. The 
first is on the whole a physical change; each fibre becomes shorter 
and broader, as if some spring had been released. No oxygen is 
used up, no carbonic acid is given off, nor any heat, but a sub- 
stance called lactic acid is split off from the muscle substance. 
The potential energy or tension of the resting muscle is converted 
by contraction into the work done, and the splitting off of lactic 
acid is somehow concerned with the transformation. But to 
restore the potential energy, so that the muscle fibre can go on 
contracting, the lactic acid has to be put back in its original place. 
This restoration process requires energy, and that is supplied by 
the oxidation of blood-sugar and perhaps some fat. Much 
oxygen is used up, carbon dioxide is given off, and heat is 
evolved. Thus we come to the main source of the production of 
animal heat. But it must be noted again that heat is produced 
in a resting warm-blooded animal by the slight contractions which 
keep up what is called the reflex tone of the muscles. Moreover, 


1004 The Outline of Science 


if part of the tension of the contracting muscle is not converted 
to external work, part of the energy will be degraded into heat. 


§ 6 


ANIMAL ELECTRICITY 


Electric Animals 


Electrical changes are known to occur in connection with 
the activity of various parts of animals, e.g. muscles, nerves, the 
retina of the eye, and glands. Similarly, when the carnivorous 
plant known as Venus’ F ly-trap shuts its leaf on an insect, there 
is an electrical change comparable to that which occurs when 
we contract a muscle—a fine instance of the unity of vital pro- 
cesses. Electrical changes have also been observed in connection 
with the movements of the Sensitive Plant, the rotation of the 
living matter inside the cells of the stonewort Nitella, and even 
in the ordinary upbuilding of carbon compounds that occurs in the 
green leaf of any plant. It looks as if electrical changes were 
associated with active vital processes in general, and this should 
be kept in mind when we pass to special cases where this trans- 
formation of energy becomes, so to speak, dominant and of high 
value in itself, as when the Electric Kel gives a shock. 


The Electric Ray 


The Electric Ray (Torpedo marmorata) of the Mediter- 
ranean is a smooth-skinned relative of the skate, and may be a 
yard long by two feet broad. It has two large electric organs 
between the front of the head and the gills, extending through 
the thickness of the body, and somewhat like flat kidneys in shape. 
Each consists of thousands (it may be half a million) of trans- 


> 


parent perpendicular prisms, or “electric plates,” separated by 
partitions. Each prism is due to the transformation of a muscle- 
fibre and its nerve-endings. When the fish is excited the dorsal 


end of each plate is electrically positive to the ventral end, and a 


Electric and Luminous Organisms 1005 


succession of shocks passes from the under to the upper surface 
of the head. If the fish is grasped a very distinct and, indeed, 
painful current passes up the arm, and this is enough to be- 
numb or even kill animals that come into close quarters with the 
Torpedo. Repeated discharges weaken the strength of the 
shocks. It is interesting to find that ordimary skate have two 
small electric organs about half-way up the tail. They are 
probably organs in process of evolution. 


The Electric Eel 

In shallow parts of the Orinoco, Amazons, and associated 
rivers, and in the marshes near by, there lives the well-known 
Electric Kel (Gymnotus electricus), which is able to stun a beast 
of burden. The fish may attain a length of 8 feet and a weight 
of 50 pounds. About four-fifths of the length is tail, and on 
each side of this there lies a huge electric organ, consisting of 
transformed muscular tissue supplied by numerous nerves from 
the spinal cord. The anterior and posterior ends of the longi- 
tudinally disposed muscle columns become oppositely electrified, 
and the current passes from the tail to the head. When the 
Electric Kel bends its body so that the head and the tail touch dif- 
ferent parts of the same fish, a very strong shock is given. Re- 
peated discharges, which may be reflex or voluntary, weaken the 
strength of the shocks, but the strongest are sufficient to kill the 
prey. Other electric organs have been found in the big-brained 
Mormyrs (Mormyride) of the Nile. The organ is situated on 
each side of the tail region, and is derived as usual from trans- 
formed muscular tissue. The shock is feeble. 


The Electric Cat-fish 

Quite different from all the other electric fishes is the 
Electric Cat-fish (Malopterurus electricus), found in rivers of 
Tropical Africa and in the Lower Nile. It is a sluggish, light- 
avoiding creature, sometimes a yard long, able to give shocks 


1006 The Outline of Science 


powerful enough to kill other fishes. ‘The electrical apparatus is 
unique in being formed of modified skin-glands, which form a 
greasy mantle all round the fish between the skin and the muscles. 
It is controlled by a single nerve-fibre arising from one huge 
ganglion-cell on each side at the front end of the spinal cord. 
The (electromotive) force of the shock in this fish amounts to 
450 volts, which is very high. The shock given by a Malopterurus 
or a Gymnotus to a man who steps on it with his naked foot is 
enough to knock him down. 

There are said to be about fifty different kinds of fishes 
that give electric shocks, but only a few of these have been care- 
fully studied. In the cases that have been investigated, with the 
exception of the Electric Cat-fish, the electric organ consists of 
transformed muscle and the associated nerve-endings. It is 
important to emphasise the fact that an ordinary muscular con- 
traction is associated with an electric change, and that the same 
is observed in glandular activity. What is ordinarily a trivial 
accompaniment of an important change becomes in the electric 
organ the main issue. ‘The electric organ discharges electricity, 
not as a current, but in a number of short shocks (lasting in Tor- 
pedo a small fraction of a second), and it is interesting to notice 
that strychnine, which throws the muscles of an animal into con- 
vulsions by acting on the nervous system, causes the Electric Ray 
to give off shock after shock in rapid succession until the creature 
is exhausted. 


Biological Conclusion 

There remains much that is puzzling in regard to the pro- 
duction of light and electricity by animals. In many cases it is 
impossible to suggest what use there may be in the luminescence, 
In many cases an electric organ also baffles us by its apparent 
uselessness. ‘The general idea that emerges is this, that a merely 
accessory by-play or by-product may persist for a long time in 
the wake of some process or result of vital significance; but that 


Electric and Luminous Organisms 1007 


the by-play or by-product may be seized upon, accentuated, and 
exaggerated when the conditions of life give it vital significance 
and survival value. 


BIBLIOGRAPHY 


Readers who wish to have further information on the subjects of this 
chapter may consult the following books: 

Bayuiss, W. M., Principles of General Physiology (1915). 

Harvey, E. Newton, The Nature of Animal Light (1920). 

Houper, C. F., Living Lights (1887). 

McKewnprick, J. G., Life in Motion (1892). 


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XXXI 
NATURAL HISTORY 


V. Tue Lower VERTEBRATES 


VOL. IV—Io 1009 


Here 


THES RASUT é 
20 ts) aS - €% 


NATURAL HISTORY 


V. THE LOWER VERTEBRATES 


HE genealogical tree of animals splits at the top into the 
| two great branches of Birds and Mammals, both of which 


may be traced back to an origin among extinct Reptiles. 
Separate articles have dealt with Birds and Mammals; it is now 
necessary to turn to the Lower Vertebrates, and a very interest- 
ing series they are. As they afford fine illustrations of progress, 
it will be convenient to begin with the most primitive types and 


work upwards. 


The Essential Characters of Vertebrates 

As far back as Aristotle (384-322 B.c.) there was a recogni- 
tion of the distinction between Backboned animals ( Vertebrates) 
and Backboneless animals (Invertebrates). It was seen that 
Mammals, Birds, Reptiles, Amphibians, and Fishes have a good 
deal in common, such as backbone and red blood, and stand by 
themselves as contrasted with molluses, spiders, insects, worms, 
sea-urchins, corals, sponges, and unicellulars, which make up 
the sub-kingdom of the Backboneless. 

Now this old contrast lasts to-day, but there are three 
changes in the modern outlook. In the first place, we know more 
clearly what are the deep differences—the most significant differ- 
ences—between the Vertebrates and the Invertebrates. 
(a) Many Invertebrates, like a lobster or an insect, have a well- 


developed nerve-cord, but this lies on the ventral surface of the 
1011 


1012 The Outline of Science 


body, and is connected anteriorly, by a ring round the gullet, 
with a dorsal brain in the head. In Vertebrates, however, the 
whole of the central nervous system lies along the dorsal middle 
line, forming the brain and the spinal cord. (b) Underneath 
the spinal cord of the Vertebrate there runs a supporting skeletal 
rod, the (endodermic) notochord, which is pinched off from the 
dorsal middle line of the embryonic food-canal. It is the support- 
ing axis of the body in a pioneer Vertebrate like a lancelot or a 
lamprey, but in most fishes and in all higher forms it is replaced 
by something better than itself—the (mesodermic) backbone. 
The notochord does not become the backbone; it is rather like a 
preliminary scaffolding—a provisional support—which is re- 
placed in most cases by a more permanent structure of different 
embryonic origin. ‘This is what is called the substitution of 
organs. 'The backbone with its numerous vertebre is the sub- 
stitute of the old-fashioned notochord. 

But it is a fine example of the past living on in the present 
that the embryos of the higher Vertebrates always have a noto- 
chord, though it is represented after embryonic life by vestigial 
traces only. As regards the notochord, even man has to climb 
up his own genealogical tree. (c) The anterior region of the 
food-canal in fishes and tadpoles shows slits, bordered by gills, 
through which flows the water that is used in breathing. In 
Reptiles, Birds, and Mammals these gill-slits are not used for 
breathing, and are not of any use at all except that the first 
becomes the Eustachian tube, leading from the ear-passage to 
the back of the mouth. But these gill-slits, never represented in 
Invertebrates, constitute an important Vertebrate character. 
The recent discovery of minute traces of gills in the embryonic 
gill-slits of two or three Birds and Reptiles shows us again how 
the past lives on in the present. (d) Another deep difference 
is that the eye of the Vertebrate has its beginning as an out- 
growth from the brain, whereas the eye of the Invertebrate is an 
ingrowth from the skin. (e) Many an Invertebrate has a well- 


Natural History 1013 


developed heart, but it is dorsal; whereas the Vertebrate’s heart 
is ventral. Thus we see that to put an Invertebrate into the 
Vertebrate position we must invert it, bringing the nerve-cord 
to the dorsal surface and the heart to the ventral surface. This 
has suggested the hypothesis that Vertebrates may have evolved 
from Invertebrates which took to swimming on their backs— 
not such a wild theory as it may seem at first sight. In any case 
the theory indicates the second change in the modern outlook— 
that we inquire into the pedigree of Vertebrates. 

There is no certainty, but there is probably most to be said 
for the hypothesis that the primitive Vertebrates were scions of 
a ringed worm (Annelid) stock. The third change that has 
come about is the recognition that Fishes are not by any means 
the lowest Vertebrates. Below the level of Fishes, there are 
the jawless lampreys and hags, and the extinct, likewise jawless, 
Hypostomes. Below these come the lancelets; simpler still the 
sea-squirts; and lowest of all are numerous worm-like forms 
called Enteropneusts which almost seem to bind the Vertebrates 
to the Invertebrates. Let us briefly consider these lowest rungs 
on the ladder of Vertebrate evolution. 


Sa! 


The Pioneers 


The Enteropneusts (their name means “gut-breathers’’) 
are certainly old-fashioned animals, and they are widely distrib- 
uted in many parts of the world. ‘They usuaily eat their way 
through sandy mud off the coasts. Probably they represent a 
side-track on the main line of Vertebrate ascent, for they are 
either Vertebrate-like worms or worm-like Vertebrates. Thus 
they have got numerous gill-slits opening from the pharynx to 
the dorsal surface of the body, and another remarkable feature 
is that the body-cavity develops in a manner closely similar to 
that seen in lancelets. The size varies from about an inch to 
several feet; the colours are bright; there is usually a peculiar 


1014 The Outline of Science 


odour like that of iodoform; the food consists of microscopic 
organisms and organic particles in the sand or mud; the sexes 
are separate. The body shows a burrowing proboscis in front 
of the mouth, a firm collar behind the mouth, a region with gill- 
slits, and a coiled posterior portion. In the proboscis there is a 
little supporting rod like a notochord, and there is a nerve strand 
both on the mid-dorsal and on the mid-ventral line. One of the 
common genera is called Balanoglossus, and besides Enterop- 
neusts in the strict sense there are some other remarkable an- 
nectent types, notably the strange Cephalodiscus, discovered by 
the Challenger expedition. They show the falsity of the frequent 
anti-evolutionist suggestion, that connecting links are always 
“missing.” The forms we have Just spoken of may not be on 
the direct line, but that they are transitional is evident. 


The Sea-Squirts 

The second rung of the ladder is represented by Tunicates, 
Ascidians, or sea-squirts, many of which are like double-mouthed 
leather water-bottles. Nothing could be less like a Vertebrate 
than a typical sea-squirt, and yet it begins its life as a free-swim- 
ming larva, like a miniature tadpole, with a brain and spinal 
cord, a distinct notochord, two gill-slits, a ventral heart, and a 
brain-eye. ‘The larva is an undoubted Vertebrate, but in most 
cases it fastens itself by its head to seaweed, stone, or shell, and 
becomes a nondescript. With great rapidity there sets in a 
progress of degeneration: the Tunicate stumbles at the threshold 
of vertebrate life. It begins well, but it does not fulfil the 
promise of its youth. In a few eases, e.g. Appendicularia, the 
larval characters are retained throughout life, exceptions that 
prove the rule. Many Tunicates form colonies and some of these 
are free-swimming, like the tubular Pyrosome or Fire-flame, 
which is sometimes 2-3 feet long and splendidly luminescent. On 
a line of their own are the glassy Salps of the Open Sea, which 
sometimes form long chains. 


Photo: Ex Step, &. LSS. 
A FULL VIEW OF THE ANGLER’S TRAP 


The Angler is not well-adapted for swimming, but it can lie almost concealed owing to its colour harmonising with the seaweeds. 
With its well-armed jaws open, and its “‘bait’’ above them, dangling in the current, it waits patiently for any passing fish to come 
within range. A touch is sufficient to make the lower jaw close witha snap. The backward-bent teeth, being hinged at their bases, 
make the entrance of the prey easy and exit impossible. 


THE PROTEUS, OR OLM 


This queer inhabitant of dark, subterranean waters was first discovered in the 
Adelsberg Cave, near Trieste. It is a blind newt, about ten inches in length, of a 
transparent fleshy-whiteness, and with persistent coral-red gills. Exposure to 
light causes the skin to develop pigment. 


a ive als 


Photo: W.S. Berridge. 
THE TUATERA 


The Tuatera of New Zealand might aptly be termed “‘a living fossil,’’ for it is the sole representative of 
an ancient group of reptiles which flourished in the age of the New Red Sandstone. It is, besides, notable 
for a rudimentary third or cyclopean eye situated deep down in the tissues of the brain. It lays its eggs 
(about ten in number) in the sand, and they are remarkable in requiring over a year to hatch out. 


Photo: W.S. Berridge. 


INDIAN CROCODILE 


These reptiles (which sometimes reach a length of 18 feet) often lurk in river shallows near fords or bathing-places awaiting an 
opportunity to seize and drag below the surface a human or four-footed victim. In addition to the terrible jaws and teeth the tailisa 
powerful weapon, while the strong defensive armour can often turn even a bullet. 


Natural History 1015 


The Lancelets 

Another class of Primitive Vertebrates is constituted by the 
Lancelets, such as Amphioxus. They are spindle shaped marine 
animals, about two inches long, translucent, fond of lying in fine 
sand with the mouth protruding, and surrounded by a wreath 
of ciliated cirri by means of which microscopic organisms and 
particles are wafted in. Now and then the lancelets rise out of 
the sand and swim about. They are archaic creatures and have 
had time to establish themselves in most seas. ‘They have so 
many negative characters—no skull, no jaws, no limbs, no brain, 
no eye, no heart, and so forth, that one begins to wonder what 
they have. But they are genuine Vertebrates—with a spinal 
cord, a notochord, and gill-clefts; and they have several features 
in common with Tunicates, to which they present no superficial 
resemblance. 


The Round-Mouths 

Before we reach the level of Fishes there is the small class 
of Cyclostomes or Round-Mouths, represented by the lampreys 
and hags. If the word fish is to mean anything, it cannot include 
these forms, for they are jawless, limbless, and scaleless, and 
they have peculiar gill-purses and an unpaired nostril. They 
are antiquities and seem to be related to a very remarkable fossil 
called Palzospondylus, which occurs in the Old Red Sandstone 
of Caithness—a little animal about the size of a tadpole, but a 
most interesting relic of early vertebrate life. Still more ancient 
are the extinct Hypostomes, also jawless, which make their 
appearance in the Silurian, e.g. Pterichthys and Pteraspis. They 
are the oldest known Vertebrates, and it is a fact to be carefully 
considered that the vertebrate stock had more than begun in 
Silurian times, many scores of millions of years ago! 

Lampreys are eel-like slippery animals, with gristly skele- 
ton, simple skull, horny teeth, and seven pairs of gill-pockets. 
The smaller kinds live in fresh water; the yard-long Petromyzon 


1016 The Outline of Science 


marinus spends most of its life in the sea, but ascends the rivers 
to spawn, dying thereafter. The young forms are called “nine- 
eyes,” though practically blind, and they remain larval for two 
or three years. Lampreys eat worms and other small fry, and 
even dead animals, but they sometimes fasten themselves aggres- 
sively to fishes, rasping holes in the skin, and sucking the flesh 
and juices. The Glutinous Hag (Myaine glutinosa) is a strange 
flesh-coloured, eel-like creature, about a foot in length, which 
lives in rather deep parts of the sea. It is a bundle of peculiar- 
ities. Thus the eye is arrested on its way out from the brain; 
under provocation the skin secretes so much slime that the old 
naturalists spoke of the hag “turning water into glue”; it seems 
to be first a male and then a female. Hags devour the bait and 
even the fish from the fisherman’s lines, and three or four are 
sometimes found inside a hooked fish. 

They are sometimes very troublesome by clogging the lines 
with slime and by biting off the bait. Of the Californian hag, 
Bdellostoma, a Chinese fisherman said with exasperation “Evely 
hook—one Sliklostome,” having learned the scientific name of 
the creature from the students of the Hopkins Laboratory at 
Monterey. 

§ 2 
Fishes 

The first Vertebrate animals to attain great success were the 
fishes, and they are as well adapted to the water as birds to the 
air. It is useful to distinguish three sub-classes: (1) the Gristly 
fishes with ventral mouth, like shark and skate; (2) the mostly 
Bony fishes, like cod and salmon, herring and eel, with terminal 
mouth; and (8) the small group of double-breathers or Dipnoi, 
which are half-way to Amphibians, having evolved a lung. These 
have all got their extinct predecessors, and there are some 
“living fossils” of great interest, like the Polypterus of African 
rivers and the Bony Pike (Lepidosteus) of North America with 
its splendid suit of chain armour. 


Natural History 1017 


In the great majority of fishes the body is torpedo-like, 
with stream-lines well suited for rapid swimming. The method 
of swimming is a kind of sculling; the posterior part of the body 
consists almost wholly of muscle and jerks off a mass of water 
on each side alternately. In a few cases, like the skates, where 
the tail has become a weapon, the paired fore-fins are used in 
swimming; in ordinary fishes they are balancing organs. Of 
course there are peculiar shapes, adapted to peculiar conditions: 
the skates are flattened from above downwards and lie on their 
ventral surface on the floor of the sea; the bony flat-fish, like 
plaice and sole, undergo in early life a flattening from side to 
side. They rest and swim on their right side or left side; pigment 
disappears from the down-turned unillumined side, which glistens 
with a silvery deposit of the waste-product guanin; the eye on the 
down-turned side travels round the corner to join its fellow on the 
upturned side, be that right or left. Then there are inflated 
globe-fishes adapted for floating on the surface of the sea; cylin- 
drical eels adapted for insinuating themselves through crevices 
or burrowing in the mud; flying-fishes able to volplane over the 
waves; and the quaint sea-horses, with prehensile tails, suited 
for a leisurely playful life among the seaweed. 

Similarly there are endless adaptations to different ways of 
feeding—the sharks intensely carnivorous, with great strength 
of jaw and an abundant succession of formidable teeth; the 
angler or fishing frog with its fishing-rod and dangling “bait,” 
and an enormous gape, bordered by backward-bent teeth, which, 
being hinged at their bases, make the entrance of the booty easy 
and the exit impossible; the mackerel depending mainly 
on minute open sea crustaceans; the carp to a great degree vege- 
tarian. Most fishes are prolific, sometimes producing several 
millions of ova; but there are some cases where the evolution of 
parental (usually paternal) care has coincided with economised 
reproduction. Thus the stickleback makes his nest; the sea- 
horse shelters the developing ova in a skin pocket; and Kurtus, 


1018 The Outline of Science 


from New Guinea, carries a double bunch about on the top of 
his head. In the great majority of fishes the fertilisation is 
external, the male discharging the “milt” (seminal fluid) on the 
“spawn” (the liberated ova); but there is internal fertilisation 
in Gristly Fishes and in viviparous Bony Fishes, such as the 
Viviparous Blenny, where the eggs hatch-out within the mother. 

Many fishes have a much less definite limit of growth than 
is usual among animals—thus a haddock sometimes occurs a 
yard long—but it is very rare for a fish to show any hint of 
senescent changes in its tissues. ‘The age is registered in the 
rings of growth in the scales and ear-ossicles. Finally, we may 
note that in the class of Fishes we have the beginnings of bone, 
of jaws, of paired limbs, of true teeth, of paired nostrils, and 
many other features. All fishes have gills, feathery outgrowths 
of the wall of the pharynx on which the blood is exposed over a 
large surface to the oxygenating action of the water. But a 
few of them, like the Bony Pike, use the hydrostatic swim- 
bladder as an auxiliary breathing organ, while in the three Mud- 
fishes or Dipnoi this structure certainly deserves the name of 
lung. In this respect, as well as in their multicellular skin-glands 
(those of fishes are almost invariably unicellular), their incipi- 
ently three-chambered heart, and the first appearance of a great 
posterior vein, resembling the inferior vena cava of higher 
vertebrates, the betwixt-and-between mud-fishes point the way 
to Amphibians. 


§ 3 

Amphibians 

The modern frogs and toads, newts and salamanders, are not 
impressive. The Japanese Giant Salamander, Cryptobranchus, 
which lives like a hermit in the dark places of cool, clear, swiftly 
flowing brooks, may attain a length of 5 ft. 3 in., but that is quite 
prodigious for a modern Amphibian. The large American bull- 
frog (Rana catesbiana) that calls from the ponds in a hoarse 


Photo: James’s Press Agency. 


SPOTTED TURTLES FIGHTING 


Turtles of various species inhabit the seas of warm latitudes. They swim actively. They come ashore to lay and bury their soft- 
shelled eggs in the sand. 


Photo: James’s Press Agency. 


ELEPHANTINE TORTOISE 


These reptiles attain a large size and may live toa greatage. They lead sluggish lives, 
their diet is vegetarian, and they move slowly about encased in the heavy armour into 
which the more vulnerable parts can be withdrawn at will. 


[ Hrsosnrirwor asses 


Photo: James's Press Agency. 


PYTHON 


These snakes grow to a very large size. They are not poi- 
sonous, but kill their prey by coiling their strong bodies round 
and round their victims. 


Natural History 1019 


bass voice “brwoom” (some observers hear it as “more rum’’) is 
only 7 inches long, or 10 if the hind-legs are stretched out. The 
fact is that most living Amphibians are pigmies, and we have to 
go back to the extinct Carboniferous forms to find the giants of 
this class. The Amphibians seem to have begun in the Devonian 
epoch (the first terrestial footprint has this date), but their 
Golden Age was in the Carboniferous. Since then they have 
gradually declined—gentle, unarmoured, weaponless creatures 
with a poor development of brains. Yet we must look to the 
ancestors of our Amphibians for many new acquisitions—fingers 
and toes for the first time, genuine ventral lungs, open communi- 
cations between the nostrils and the mouth, a three-chambered 
heart, and a mobile muscular tongue. With few exceptions the 
young stages of Amphibians breathe by gills, and these are some- 
times retained throughout life, as in the Proteus of the 
Dalmation caves. But all adult Amphibians have lungs except 
a few abnormal newts. And the skin is also capable of cutaneous 
respiration, as our frogs illustrate in their winter’s rest. The 
greatest interest of Amphibians is that they were the first 
Vertebrates to colonise the dry land, and that most of them 
recapitulate in their individual life-history to-day some of the 
steps in that great adventure. 


Reptiles 
Lizards, snakes, tortoises, crocodilians, and the archaic — 
Sphenodon of New Zealand—another “living fossil” —represent 
the reptiles of to-day, and they had their extinct prede- 
cessors. But besides the latter, which are continued on in their 
modern descendants, there were many ancient stocks that have 
entirely ceased to be. Thus the flying dragons or Pterodactyls 
have had no successors, and the same is probably true of Ichthy- 
osaurs and Plesiosaurs. The blood of some of the Dinosaurs 
may still be flowing, so to speak, in birds and mammals, which 
evolved from that progressive and heterogeneous stock; but there 


1020 The Outline of Science 


are other reptilian branches on the genealogical tree which bear 
no leaves to-day. It was probably in the Carboniferous epoch 
that Reptiles evolved from their Amphibian ancestry; in the 
Permian they were the dominant Vertebrates. 

The New Zealand Tuatera (Sphenodon) belongs to an 
order by itself, of which it is the sole survivor. It was in it first 
of all that the pineal body—an upgrowth from the roof of the 
tween-brain (optic thalami)—was recognised as having distinct 
traces of an eye, e.g. complex retina. This rare animal, 1-2 feet 
long, is preserved in some small islands off the New Zealand 
coast, surviving as best it can in virtue of its “cryptozoic”’ or 
elusive habits. It lives in a burrow, feeds on insects, worms, 
and other small creatures, and comes out at night. It sometimes 
shares its hole with a petrel. About ten eggs are laid in the warm 
sand, and they are remarkable in requiring over a year to hatch 
out. As in the case of other archaic types, the development of 
Sphenodon is of great zoological interest. 

Crocodiles and alligators and the long-snouted gavials are 
strong, heavily armoured reptiles, at home in tropical rivers, 
clumsy and stiff-necked on land, feeding on fishes and small 
mammals, growing very slowly and without obvious limit, and 
attaining a great longevity. They often lie in wait for their 
victims at the water’s edge, and drown them, being themselves 
able to breathe while the mouth is full of water. For they shunt 
the opening of the windpipe forward to embrace the posterior 
nostrils, situated at the end of the bony tunnel at the very back 
of the mouth. When the crocodile raises its nostrils above the © 
surface of water during the drowning operation, the air can pass 
continuously to the lungs, and no water can go down the wrong 
way. The crocodilians have a four-chambered heart as in birds 
and mammals, but they remain cold-blooded. ‘They are the only 
Vertebrates other than mammals to have teeth in sockets, and if 
one be broken there is another and another ready to replace the 
loss. In other words there are many sets of teeth. The eggs are 


Natural History 1021 


like those of geese and are buried in the soil to be hatched by the 
heat of the sun, sometimes abetted by decaying vegetation. In 
some cases the mother digs up the hatching eggs when she hears 
the young ones piping from within. The Indian crocodile may 
reach a length of 18 feet, and the gavial may be 2 feet longer. 


Tortoises and Turtles 

Tortoises are among the most perfectly armoured of ani- 
mals, surpassed only by the armadillos. They are boxed in by an 
arched carapace above and a flat shield below, and they can 
partially retract their head, tail, and limbs. They are almost 
invulnerable. They tend to be slow in growth and slow in move- 
ment; they have a very tough constitution and can endure pro- 
longed fasting. The tissues are famous for their tenacity of local 
life; thus the turtle’s heart will beat for two or three days after 
the rest of the animal has been made into soup. 

The Lacertilians or lizards form a very heterogeneous order. 
They are usually active in their movements, but fond of basking 
in the sun; many of them are resplendent in their colouring, while 
others harmonise to perfection with their immediate surround- 
ings; most of them are able to surrender the tail when seized by 
an enemy and to regrow it at leisure. Most lay eggs, but a few, 
like the British brown lizard, are viviparous. The only poisonous 
lizard is the Mexican Heloderma; the Chameleons are adapted 
for arboreal life and are famous for their colour-changes; the 
Phrynosome or “Horned Toad” of Texas and Arizona is full 
of curiosities, e.g. in having an eyelid hemorrhage when much 
excited; the little Dracos of the Far East swoop from tree to 
tree on collapsible parachutes of skin extended on much elon- 
gated ribs; the snake-like slow-worms and Amphisbenas are 
suited for burrowing in the earth. Perhaps there is no order of 
Vertebrates so diversified as the lizards. 

The most highly specialised of the Reptiles are the snakes 
or serpents (Ophidia). Apart from rudiments of a hip-girdle 


1022 The Outline of Science 


and the vanishing points of hind-legs in pythons, boas, and a few 
others, snakes are thoroughly limbless, and there is no hint of 
shoulder-girdle or breastbone. They row on the ground with the 
ribs, which are attached to the ventral scales; and they may jerk 
themselves forward by a rapid straightening of their sinuous 
curves. Yet they swim and climb and burrow. The mouth is 
very expansible and suited for booty large in proportion to the 
size of the head; the bifid tongue is a sensitive organ of touch; a 
pair of salivary glands may be transformed into poison glands; 
the poison fangs are teeth folded to make a groove or a canal 
for the venom; the internal organs of the body are adjusted to 
the great elongation; the outermost layer of the epidermis cover- 
ing the horny scales and taking their imprint, is peeled off and 
turned inside out from the head to the tail as a coherent 
“slough”; most are oviparous, but the adder and some others 
have developed viviparity. 

Such, then, is a survey of the Lower Vertebrates: the worm- 
like Enteropneusts, the Sea-Squirts, the Lancelets, the Round- 
Mouths, the Fishes, the Amphibians, and the Reptiles. From 
among the last there arose the Higher, Warm-blooded Verte- 
brates—the Birds and the Mammals. 


BIBLIOGRAPHY 


Guntue_er, The Study of Fishes (1880). 

Ossporn, H. F., The Origin and Evolution of Life (1918). 

Pycrartr, W. P., The Story of Fish Life (1905) and The Story of Reptile 
Life (1905). 

Reean, C. Tare, British Freshwater Fishes (1911). 

Tuomson, J. ArtHur, The Study of Animal Life (4th edition) and Outlines 
of Zoology (7th edition). 


XXX 


THE EINSTEIN THEORY 


; 


THE EINSTEIN THEORY 


Are Things What they Appear? 
ET us see what some of the startling ideas of Einstein are 
| i which have upset many of our fixed notions about things. 
We have been taught that parallel lines never meet, that 
the shortest distance between two points is represented by a 
straight line. According to the Einstein theory what we think 
are straight lines are “really” curved lines. We shall under- 
stand this point better later on. Meanwhile, suppose you draw 
a straight line on a sheet of paper. ‘To you, looking only at the 
paper, the point of the pencil will have travelled in a straight 
line of, suppose, a foot long in a second. To an observer in the 
sun it will have moved through space, not only with the motion 
of your hand, but through the vast curve of the earth’s spin round 
its axis, and the still vaster curve of its rotation round the sun. 
Where you see a short straight line he will see a curve some forty 
miles in length. Which is right? Both. The distance, as well 
as the straightness or curvature, described by a moving point is 
relattve—they depend on the observer. 

Motion and direction are relativue—they depend on the ob- 
server. A body alone in empty space cannot be said, with any 
meaning, to be in motion; for motion implies that it is getting 
nearer to, or farther from, some other point. Again, if there 
are two such bodies which start moving side by side, but at 
different speeds, an observer on the swifter body will see the other 
apparently receding from him. ‘To an outside observer it will 
appear to be following in his wake. Which is right? Both. 
Motion and direction are relative—they depend on the observer. 


VOL. 7v—IT 1025 


1026 The Outline of Science 


If you were sitting in a railway carriage with the window 
blinds drawn, the train running smoothly on a straight track with 
unchanging velocity, you would find it impossible to tell by any 
mechanical means whether the train was moving or not. You 
cannot detect in such circumstances any motion without refer- 
ence to some outside object. Further, you may have noticed 
that if you look through the carriage window at a passing train 
on an adjoining line you are unable to tell whether that train or 
your own is in motion. In this way we are often puzzled to say 
whether some train is moving with us, or against us, or standing 
still. All motion is relative. 

All this is preliminary—we shall see the bearing on Ein- 
stein’s argument later. 

Space also is a matter of relativity. What would become 
of space if you took everything out of it? It would have no 
meaning; we cannot form any idea of empty space. ‘There is 
no such thing as absolute space. If the whole of our visible uni- 
verse were compressed into the size of an orange, we should be 
quite unaware of any change. Our measures, reduced in propor- 
tion, would still, for example, show the sun to be ninety-three 
million miles away. Size is relatitve—it depends on the observer. 

It is our measuring rods which create space for us, it is by 
measures we determine the position of material bodies in space; 
we can only measure the distance from a body at a certain point 
of space to a body at some different point. 

And so with Time. Has it any reality? “What would be- 
come of time if nothing ever happened.” ‘Time is merely a local 
affair. As the measuring rod creates space, so it is clocks which 
create time. We cannot form any idea of absolute time or of 
absolute space. As we shall see, we make a wrong supposition if 
we suppose 


that an interval of time and an interval of space between 
two given phenomena are always the same for every ob- 


The Einstein Theory 1027 


server, whatsoever and whatever the conditions of observa- 
tion may be. 


We cannot measure time itself—we can only measure it by the 
motion of something over a space, as a clock hand or a planet. 
But, as we have seen, motion and space are not real existences 
but relative. They depend on the observer, and so does time. 


If some malicious spirit were to amuse itself by making all 
the phenomena of the universe a thousand times slower we 
should not, when we awake, have any means of detecting 
the change. Yet every hour recorded by our watches would 
be a thousand times longer than hours had previously been. 
Men would have lived a thousand times as long, yet they 
would be unaware of the fact. 


We shall see in a moment that Time and Space, according to 
Einstein’s theory, are to be regarded as mere properties which 
we ascribe to objects. 

One more point: “the dimensions of an object, its shape, 
the apparent Space occupied by it, depend upon its velocity”’; 
the size and shape of any body depend upon the rate and direc- 
tion of its movement. | 

One of the most revolutionary things about the Einstein 
theory has to do with Newton’s Law of Gravity. 


A. New View of Gravity 

Einstein thinks that gravity is not, as Newton held, a force, 
but a property of space. That all the effects of gravity may 
exist where there is no attraction is best shown by his own strik- 
ing illustration. Imagine a chamber, like that of the projectile 
in Jules Verne’s story, alone and motionless in empty space. A 
passenger therein will have no weight—his feet will not press 
downward on the floor. If he throws a ball into the air it will rise 
to the roof and remain there—there is no force of attraction to 
bring it down again. A weight hanging on a spring-balance will 


1028 The Outline of Science 


not stretch the spring. Now suppose that the chamber begins to 
move with a velocity which is continually increasing at the same 
rate as that of a body falling on the earth. The floor will press 
upward against the passenger’s feet; it will catch up the ball, 
which will appear to be falling; the balance, drawn upwards 
against the inertia of the weight, will measure its amount pre- 
cisely. There is no possible experiment which the passenger can 
make which will show him whether the projectile is moving with 
an accelerated motion or whether it is at rest, as we imagine we 
are, on the surface of an attracting body. ‘This last, indeed, is 
what he will imagine. But he may be under a complete illusion— 
and so may we. 

This is Einstein’s “Theory of Equivalence.” It shows that 
gravitation may have more than one explanation. And _ this 
leads us to his own explanation, which is an altogether new one. 

Newton thought the apple fell because the earth exerts upon 
it an attractive force. Einstein considers that it falls because, 
wherever there is matter, space itself is curved, Just as the space . 
we see in a very slightly concave mirror, where there are no 
straight lines at all, and where, if any body is in motion, it must 
move along a curve. Suppose a man in a closed room discovers 
that a marble placed anywhere against a wall rolls towards a 
hassock in the centre of the room, it will appear to him that the 
hassock is. attracting it. Yet the fact may be that the floor is 
slightly concave, like a very shallow basin, and the hassock has 
no connection whatsoever with the motion of the marble. Just 
in the same way the earth may have no direct connection with the 
falling of the apple, though it seems to us to be the cause of it. 
We are asked to believe that space is curved, that all things 
moving through it move in curves—all things including light. 
Einstein’s theory asserts that the actual reality which underlies all 
the manifestations we experience in the physical universe is a 
blend of time, space, and matter. This trinity is comprised in one 
actual reality. All bodies move through space-time; and they 


The Einstein Theory 1029 


move in the straightest possible tracks; motion is merely simul- 
taneous change of position in space and time. Einstein’s theory 
explains gravitation as distortion of the world of space-time due 
to the presence of material objects. He does not explain how or 
why a body can distort space-time; the theory explains gravity, 


not as a force of nature, but as a property of space-time. 


On Einstein’s view of gravitation, the earth moves in an 
elliptical path around the sun, not because a force is acting 
on it, but because the world of space-time is so disturbed by 
the presence of the sun that the path of least time through 
space is the elliptical path observed. ‘There is therefore no 
need to introduce any idea of “force” of gravitation. 


The more matter is present, the more space is curved. And so 
it happens that the light from a star just behind the sun will come 
bending round it, like a train round a railway curve, and fall upon 
our eyes or cameras—that is, when the sun’s glare is shut out 
during an eclipse—and we can see or photograph the star. It 
will appear to be shifted from its true position—how far shifted, 
Einstein has worked out. At the last eclipse the stars appeared 
where he had predicted. 


§ 1 
The Curvature of Space 
One of the great difficulties of Einstein’s theory is, of course, 
the assumption that space is curved, so that “straight lines’ in 
this curved space are not the straight lines that Euclid talks about. 
But we can see how this may be possible if we first consider the 
matter in a simple form. 

Let us imagine intelligent creatures who exist in only two 
dimensions, i.e. they have length and breadth, but no thickness—a 
sort of very intelligent flat-fish, Suppose they exist on a 
plane—like the surface of this sheet of paper. Then the 
geometry they construct will be like Euclid’s. They will find, 


1030 The Outline of Science 


for instance, that a space cannot be enclosed by two straight lines. 
You must have at least three straight lines (a triangle) to en- 
close a space. And they will see that a straight line can go on for 
ever and ever. Also it will be quite easy for them to draw any 
number of lines parallel to one another. But now suppose that 
these little flat creatures are transported to the surface of a sphere. 
What sort of geometry will they now construct? 

Now, first of all, we must remember that, by hypothesis, 
they have no notion of a third dimension. They cannot go inside 
or outside their sphere. They have no notion that any space 
exists except the actual surface of their sphere. What will they 
call a straight line? They will say that a straight line is the 
shortest distance between two points. Well, let us take any 
two points on the surface of the sphere and join them by the 
shortest line, keeping to the surface of the sphere. 'This line will 
be, from our three-dimensional point of view, an arc of a circle. 
And no parallel “straight” lines can be drawn to it by the 
creatures on the sphere. Further, let us select two points at 
opposite ends of a diameter of the sphere. Through these two 
points an infinite number of half circles can be drawn, all of the 
same length and all shorter than any other kinds of curves uniting 
these two points. That is to say, from the point of view of the 
flat inhabitants, an infinite number of different “straight lines” 
pass through these two points. And any two of these straight 
lines enclose a space—just as any two lines of longitude on the 
earth, running from the North to the South Poles, enclose a 
space. Now these properties of the straight line contradict the 
axioms of Euclid. The geometry developed by these creatures 
will not be Euclid’s geometry. 

If they are very expert geometricians they will say that their 
space must be curved—as we know it is. And they will be 
able to measure how much their space is curved by making 
measurements on the figures they can draw. Now what Einstein 
asks us to do is to imagine something similar about our own 


APPARENT 


ACTUAL 
POSITION 


OF STAR 


VAs 
wt * 
ss 


OBSERVER 


a 


THE CURVE OF THE 
STAR-RAY SHOWS THAT 
SPACE IS CURVED IN 
PRESENCE OF MATTER 
(THE SUN). UPON THIS 
FACT EINSTEIN’S 
THEORY OF GRAVITY 
IS FOUNDED 


A certain curvature 
would be expected on the 
electro-magnetic theory of 
light, but the curvature 
predicted by Einstein’s 
theory was double that 
which the older theories 
predicted. Einstein’s 
value for the deflection 
was handsomely confirmed 
by observation. This ex- 
perimental result is justly 
regarded as a crucial veri- 
fication of Einstein's 
theory. 


THE APPARATUS OF THE FAMOUS MICHELSON-MORLEY EXPERIMENT 
REFERRED TO IN THE TEXT 


This was devised in the manner shown above in order to test the velocity (if any) of the 
earth relative to the sea of ether. A number of mirrors were arranged on a solid table 
floating on a circular bath of mercury. Alampthrewa ray of light, which was divided by 
partial reflection at a thinly silvered surface into two parts, running at right angles to one 
another. It was hoped that by revealing a difference of speed the motion through the 
ether could be determined. But to the experimenters’ surprise no difference was discern- 
ible. The experiment was tried through numerous angles, but the motion through the 
ether was nil. (See diagram on following page. The text makes the connection between 
these two diagrams clear.) 


THE SHIP 


> 


A SHIP AT SEA DETERMINING ITS MOTION. (A COMPARISON WITH THE FAMOUS MICHELSON-MORLEY 
EXPERIMENT CONCERNING THE ETHER) 


Newton said that the motion of bodies in a given space is the same among themselves whether at rest or moving forward, and 
quoted as example the people and thingsinaship. Noexperiment on board the ship itself discloses the vessel’s velocity through the 
sea. ‘‘ The matter stands differently,’’ writes Mr. J. H. Jeans, ‘“‘to one who is free to experiment with both the ship and the sea. 
Let a sailor drop his lead into the sea, a circular ripple will spread out; but every sailor knows that the point at which his line enters 
the water will not remain at the centre of this circle. The velocity with which the point of entry advances from the ‘centre of the 
circle will give the velocity of the ship throughout the sea. If our earth is ploughing its way through a sea of ether, an experiment 
conceived on similar lines ought to reveal the velocity of the earth through the ether.’”’ (See diagram on preceding page.) 


The travellers = If you fravelled with the velocity oF : 
ae sound (1120 feet per sec) you would 
Co never hear the nexf toll. 


Lo bes 


This diagram will make it clear that a traveller moving with a greater speed than that of asound-wave will never hear the toll of the 


bell—the sound is not moving fast enough to catch him up. This will make it easier to understand the same principle applied in the 
following diagram to the case of light. 


The hands of a clock Hiak fs travelling 


away seem fo move slower fhan one 


close at hand. 


SP IT 
ee 
ee in me 


. Lf the clock travelled away with 
the velocity of light: the hands 

would appear fo remain for ever 
_at the same point: 


S000 ee ee ne ne CO. i ari ei i Sei eis 


The apparent movement cf the hands ot a clock travelling away will be clear from this diagram, taken together with the one above. 
If the clock is travelling away at the same speed as light the hands of the clock will apparently never move. 


The Einstein Theory 1031 


space. Actual measurements of our space show that its geometry 
is not Euclidean. We can, therefore, as if by an analogy, talk 
about the curvature of our space. 

Now there is another important analogy between our space 
and the surface of the sphere. What happens to a “straight line” 
on the sphere when it is produced? It goes all round the sphere 
and comes back to the point it started from. It cannot, that is to 
say, go on for ever and ever. The curvature of the surface bends 
itround. The space these creatures live in is a finite space—it does 
not go on for ever and ever. At the same time it is unbounded— 

‘there are no barriers. The flat creatures can wander about in 
their space as long as they like without ever meeting an obstacle 
to their further progress. Nevertheless, although unbounded, 
their space is not infinite. Einstein says that the same distinction 
holds good of our space. Our space, he says, is finite; the ray 
of light from a star would go on until it went all round the 
universe and came back to its starting-point. But our space is 
also unbounded. We could wander about in it for ever; we 
should never come to a notice saying “Thus far, and no farther.” 
But when we had wandered far enough, going quite “straight” as 
it would appear to us, we should come back to our starting-point. 


§ 2 
Such are some of the revolutionary ideas imported by Ein- 


stein’s theory. Let us now discuss this theory a little more closely. 


The Theory of Relativity 

Einstein’s Theory of Relativity is probably the most pro- 
found and far-reaching application of mathematics to the phenom- 
ena of the material universe that the world has ever known. 
Yet in spite of the very abstruse nature of the theory it is no 
paradox to say that its object is to give us a simpler, a less 
sophisticated, view of the universe. We are sometimes apt to 
forget that the human consciousness is a very complicated and 


1032 The Outline of Science 


highly developed thing. Our minds represent a development that 
has extended through hundreds of thousands of years. It is very 
likely that some of the ideas which seem to us simplest are really 
complicated abstractions; the race has built up certain ideas 
because it found it useful to build them up in that way. We now 
take those ideas for granted, but that does not alter the fact that 
they are elaborate and, in a way, artificial constructions. It often 
requires as much, or greater, insight to analyse our ideas into their 
primitive constituents, as to build up still more complicated ideas 
on the basis of them. 

Now the chief characteristic of Einstein’s theory is that it 
takes us behind our present ideas about space, time, and matter, 
to the primitive reality out of which we have built up those ideas. 
We can see the nature of the theory most clearly if we begin 
at the end. Imagine some entirely fresh, inexperienced intelli- 
gence to be suddenly put in a field in our world on a summer day. 
This intelligence has at first a general awareness of the field, 
and everything in it, asa whole. We will suppose that this intelli- 
gence is essentially a human intelligence, and that after a little 
it begins to discriminate. It begins to distinguish parts of the field 
from other parts of the field. What sort of discrimination will this 
be? The intelligence will be aware of itself and of the field. 
We suppose the intelligence has a body; this will give it, as it 
were, a centre to work from. It will begin to distinguish between 
here and there. Suppose the intelligence has been watching a 
wasp on a flower. The wasp and the flower make just one 


indivisible whole for it. The whole thing—wasp and flower—is 
there. Presently the wasp detaches itself from the flower and 
settles on the hand of the intelligence. Part of the object that 
was there is now here. And if the wasp now stings the hand of 
the intelligence this event will occur after the wasp had formed one 
object with the flower. Here and there, before and after, in- 
troduce the notions of space and time. And if the intelligence 


agreed that the same wasp appeared on his hand as was on the 


The Einstein Theory 1033 


flower, he would obtain the idea of objects that persisted in 
space and time—that were the same at different parts of space 
and at different points of time. He would thus begin to form 
the notion of matter. 


The Fourth Dimension 

Now we do not profess that this is an accurate account of 
how much an intelligence would split up the primitive reality into 
space, time, and matter, nor do we say that this is the actual 
path that has been pursued by the intelligence which culminates in 
man. We have introduced this illustration to give the reader 
some preliminary inkling of what is meant when we say that 
EKinstein’s theory has combined space, time, and matter into one 
unity. If the main idea is once grasped, however imperfectly, 
the way to understanding the broad outlines of the theory is made 
easy, although the details can only be followed by skilled mathe- 
maticians. The theory asserts that the actual reality which under- 
lies all the manifestations we experience is neither spatial nor 
temporal nor material, but a blend of all three. It is we who 
have split up the original unity into the three entirely different 
things we call space, time, and matter, and we have performed 
this feat either because it was a very useful way of dealing with 
reality, or because our minds could not function in any other 
way. Let us consider first the division into space and time, and 
let us ask ourselves what this division really means. Let us 
take a solid body having length, breadth, and thickness—say a 
cube. What is implied in the existence of a cube? This problem 
is discussed in Mr. H. G. Wells’ excellent story The Time 
Machine, written years before Einstein’s theory was thought of. 
The Time Traveller asks: 

“Can an instantaneous cube exist?” 

“Don’t follow you,” said Filby. 

“Can a cube that does not last for any time at all, have a real 
existence?’ 


1034 The Outline of Science 


Filby became pensive. 
“Clearly,” the Time Traveller proceeded, 


any real body must have extension in four directions: 
it must have Length, Breadth, Thickness, and—Dura- 
tion. . . . There are really four dimensions, three which we 
call the three planes of Space and a fourth, Time. There is, 
however, a tendency to draw an unreal distinction between 
the former three dimensions and the latter, because it hap- 
pens that our consciousness moves intermittently in one 
direction along the latter from the beginning to the end of 
our lives. 


The matter could not be put more clearly, and it is scientifi- 
cally quite accurate. As the Time Traveller says a little later, 
“there is no difference between Time and any of the three di- 
mensions of Space except that our consciousness moves along it.” 
Einstein’s theory states that, from the point of view of science, 
there is no essential distinction between time and the three 
“dimensions” (Length, Breadth, Thickness) of Space. Science 
is not concerned with our feelings about the difference. Before 
and after appears to us as a much more fundamental difference 
than before or behind, above or below, right or left. But Einstein 
has proved that time enters into physical phenomena in the same 
way as the directions in space. That is what is meant by saying 
that the world is four-dimensional. Everything which happens, 
happens somewhere at some time. Two events are separated 
from one another not only by their position in space but by their 
position in time. Now all this is fairly elementary; we have seen 
that some people, like Mr. Wells, had a pretty clear idea of it 
before Einstein’s theory appeared. But Einstein takes us a big 
step further. He asked a question which nobody had asked till 
then. Is the space and time interval which separates two events 
the same for everybody? 

Let us see what this question means. Suppose you are 


The Einstein Theory 1035 


running a race—one hundred yards—and suppose all the 
spectators have absolutely perfect watches. Suppose the judge 
declares that you have run exactly one hundred yards in exactly 
eleven seconds. That is to say, that between the event when you 
left the starting-line and the event when you breasted the tape 
at the other end, there is a space interval of 100 yards and a time 
interval of 11 seconds. Will all the spectators agree upon that? 
Common sense says they will, and common sense is quite right. 
But now suppose that at the instant you began to run, an aviator 
flying at 100 miles per hour flew above you, and suppose he 
watched your sprint from start to finish. We also suppose he 
has absolutely perfect measuring instruments with him, so that 
he can measure the length of the course you are running and the 
time you take. Will he agree with the stationary spectators? 
Common sense says that he will, but here Einstein, using mathe- 
matical proofs which would be out of place in this article, says 
that he will not. He will not agree, firstly, that you ran exactly 
one hundred yards nor, secondly, that you took exactly eleven 
seconds to do it. He will disagree with the judge both in his 
space and time measurements. Now this conclusion shocks us at 
first; but why should it? We have already seen that the reality 
of the world is an inextricable blend of space and time. We sort 
this blend out into space and time to suit ourselves. But why 
should we say that everybody always sorts it out in the same way? 
We know that different people can have different opinions about 
exactly the same thing. A political speaker may appear to one 
man to be a wise statesman talking to intelligent and patriotic 
citizens. Another spectator of exactly the same event may see 
a cunning rogue talking to a lot of fools. We explain this dif- 
ference by saying that the two men have had different upbring- 
ings, different experiences, and so on. But can we be quite sure 
that no change of circumstances makes two observers of the same 
reality split it up differently into its space and time factors? As 
a matter of fact Einstein has shown that they will not split up the 


1036 The Outline of Science 


reality in the same way if their motions are different. But the dif- 
ference of motion necessary to make the change appreciable is 
enormous. 

We have said that our aviator, if he had perfect instruments, 
would disagree with the judge. But in truth, his instruments 
would have to be a million times more perfect than the best in- 
struments we can make before there would be any likelihood of 
him and the judge quarrelling. No velocities that we can reach 
on earth would make the faintest observable difference to our 
space and time measurements, for we are not able to travel at 
several thousands of miles per second. ‘That is why we have 
always supposed these measurements to be exactly the same. 
They are, for all practical purposes. But as a scientific fact they 
are not. Things which happen at the same time for an observer 
at rest do not happen at the same time for an observer in motion. 
But unless the observer in motion is moving at hundreds or thou- 
sands of miles per second, the best earthly instruments would 
show no difference. ‘The actual mathematics of the problem show 
that the aviator would find the hundred yards rather shorter than 
one hundred yards, and the eleven seconds rather less than eleven 
seconds. But the difference, as we have said, is impossible of 
detection with our instruments. Even if the aviator were moving 
at 67,000 miles per hour, which is the earth’s velocity round the 
sun, the judge’s watch would seem to lose only 1/2300 second per 
day. And a one-foot rule would appear shorter by only one | 
seventeen millionth of an inch. 

But the difference mounts up rapidly as the speed increases. 
At 161,000 miles per second, for instance, a velocity which is in 
the neighbourhood of the velocity of light, the watch would lose 
twelve hours per day, and the foot-rule would become six inches 
long. At the velocity of light itself, the watch would not seem 
to be going at all, and the foot-rule would have shrunk to nothing. 
The velocity of light, therefore, is a theoretical absolute limit. 
No greater velocity is possible. 


The Einstein Theory 1037 


Doubtless these results seem fantastic at first sight. “A 
second is a second,” you might say, “and a foot is a foot.” But 
you have already been predisposed to believe that space and time 
themselves are not ultimate realities; the actual reality is a kind 
of union of the two. Now the apparent paradox of Einstein’s 
theory is removed when we discover that there is a certain com- 
bination of space and time measurements on which everyone 
agrees, whatever their state of motion. ‘They split up this com- 
bination differently, yes; but they agree on the combination. 


3 

The Test of Experiment | 

The theory that we have been expounding is necessitated by 
the very extraordinary experimental fact that all observers, how- 
ever fast they may be moving, find the same value for the velocity 
of light. The most careful test of this statement that has been 
made is the famous Michelson-Morley experiment. We can see 
what this extraordinary result means if we think of a bird flying 
from one end of a train to the other. If the train is at rest the 
bird takes a certain time for the journey. If the train is moving 
towards the bird it takes a shorter time; if the train is moving 
away from the bird, the bird takes a longer time. Here every- 
thing is as it should be. But Michelson and Morley found that if 
a ray of light, instead of the bird, is the flying thing, it takes 
exactly the same time in all three cases! How can that be? Here 
Hinstein’s theory gives a complete explanation. We are measur- 
ing the distance flown and the time taken from the train. But 
our measurements of distance and time vary, as we have seen, with 
our motion—and to exactly the extent required to produce com- 
plete compensation, so that in each case the measured velocity of 
light will be exactly the same. And this remains true however 
fast the train may be going. We must always remember that 
Kinstein’s theory, however strange it may appear at first, rests 
on experiment. It is no unsupported flight of the mathematical 


1038 The Outline of Science 


fancy. To those who will not accept the theory we may fairly 
say—‘“Well, how do you explain the experiments?” 


Turning Time Backward 


In order to free our minds from preconceived ideas of Time 
and Space, let us take an illustration from the scientific romance 
Lumen, by the celebrated French astronomer Flammarion. It 
relates how the soul of a man, on his death in 1864, flew with the 
speed of thought to one of the stars in the Constellation Capella, 
situated at a distance from the earth which light takes 72 years 
to travel, so that he found the inhabitants watching, with their 
supernatural telescopic eyes, the events of the French Revolu- 
tion, of which the light-rays were just reaching them. The man’s 
soul, flying further with a speed greater than that of light, so that 
he overtook the light-rays that had long left the earth, saw events 
occurring backwards, like a cinema film driven the wrong way. 


When I recognised the field of Waterloo, I saw at first a 
number of dead bodies stretched upon the ground. Beyond 
them I saw Napoleon arriving backwards holding his horse 
by the bridle. Then I saw the dead soldiers come suddenly 
to life and spring to their feet. The horses came to life again 
at the same time and their riders sprang into the saddle. As 
soon as two or three thousand men were thus resuscitated, 
they gradually reformed their ranks. ‘The two armies began 
to fight with fury. In the centre of the French army I 
perceived the Emperor, surrounded by his soldiers. The 
Imperial Guard had come to life again! At the end of the 
day not a single man was killed or even wounded—not a 
uniform was torn. 'T'wo hundred thousand corpses, come to 
life, marched off the field in perfect order. And the result 
of this strange battle was not to vanquish Napoleon, but on 
the contrary to restore him to the throne! 


The Einstein theory does not stop here. It goes on to 
prophesy that a mass of matter, a pound weight, for instance, 


The Einstein Theory 1039 


increases in mass as it travels faster. Here, again, the increase 
in mass is not appreciable at ordinary speeds. Hven at 67,000 
miles per hour a pound mass only increases by one two hundred 
millionth of a pound. But at 161,000 miles per second its mass is 
doubled—it increases by one pound. And at the speed of light its 
mass is infinitely great. So that here, again, we see that the 
velocity of light is an ultimate velocity. Now we actually have 
samples of bodies moving with enormous velocities. ‘The cathode 
rays, for example, and some of the particles shot out by radium, 
have velocities very much greater than we are in the habit of 
dealing with. The increase of mass of these particles due to their 
velocities can be calculated, and here again the experimental facts 
confirm Kinstein’s theory. If we lived in a world where velocities 
in the neighbourhood of the velocity of light were common we 
should have known all about Ejinstein’s theory long ago; we 
should find nothing paradoxical in it; it would seem quite com- 
monplace. 


Space and Time Blended Together 

So far we have been describing what is called the special 
Theory of Relativity, which was published by Einstein in 1905, 
when he was 27 years of age. Since then, as all the world knows, 
he has taken an immense step forward. He has greatly extended 
his theory so as to include gravitation, and, as one consequence, 
he has shown that space, or rather, the space-time unity we have 
spoken about, does not obey Euclid’s geometry. But although 
this Generalised Theory of Relativity is probably the profoundest 
single achievement of the human mind, it is not impossible to 
get an idea of its essentials on the basis of what we have already 
said. We have seen that it is not sufficient to think of space and 
time as existing separately. In reality they are blended together. 

Now the further question arises, does matter exist in- 
dependently of space and time? We must make our question 


more precise. Are we to conceive space and time as forming a 


1040 The Outline of Science 


sort of framework within which matter exists and in which it 
wanders about quite independently? Has matter no actual 
influence on space and time? To answer this question rightly we 
must get rid of certain philosophical assumptions. We all make 
these assumptions, whether we know it or not, and even if we have 
never read a line of philosophy. The assumptions belong to those 
complicated ideas built up by the race to which we referred at 
the beginning of this article. Now when Einstein asks this 
question he is asking it about a space and time that we can 
measure by rigid measuring rods and clocks. He makes the 
whole subject experimental. We must remember this in what 
follows. 

Firstly, it will make the subject clearer if we go back to 
Newton. Newton said, in his first law of motion, that a moving 
body acted on by no forces moves in a straight line and always 
with the same speed. Well, now, how did he know? Where are 
we to find a body acted on by no forces? Certainly not on the 
earth, for the earth is a large rotating mass, and every body on 
it is acted on by the earth’s attraction, and also by the centrifugal 
force set up by its rotation. The fact is that Newton’s law is not 
an experimental law. It sounds so reasonable, and was accepted 
by the scientific world for centuries, simply because it appeals to 
our unconscious assumptions about the nature of space. We 
always assume, in fact, that Euclid’s geometry holds good of 
actual space. 

But now see what happens as a consequence of this. If we 
look up into the sky and watch the planets we find that they are 
not moving in straight lines. Why? “Because they are acted on 
by forces,” says Newton. The natural, unconstrained motion of 
a body, he says, is a straight line. Consequently, if we find that 
it is not moving in a straight line, it is necessary to suppose that 
it is not unconstrained—some force must be deflecting it. So that 
we first of all start with a motion that nobody has ever observed 
and call that the natural motion, and then all the motions we do 


The Einstein Theory 1041 


observe require the invention of forces to explain them. It is 
needless to say that we are not now trying to underrate Newton’s 
wonderful achievement; we are simply preparing the way for 
another point of view. The other point of view is this: the actual 
motions of the planets are their natural motions; we require no 
“forces” to explain them; they move in the way they do, not 
because they are pulled continually out of their natural path, 
but simply because that is their natural path. But, you say, they 
do not move in straight lines! Einstein’s answer is: No, but 
motion in a straight line is only natural in a Euclidean space; it 
must be that our space is not Euclidean! 


The Great Prediction 

We have, then, these two points of view. Newton says that 
space is Euclidean, and that the natural motion is a straight 
line. The planets move in this Euclidean space, and the fact that 
they do not move in straight lines is explained by saying that there 
is a force, “gravitation,” pulling them towards the sun. Einstein 
says that space is not Euclidean, and that no “forces” are re- 
quired to explain the motion of the planets; their motion is the 
natural one in the sort of space they exist in. How are we to 
decide between these points of view? There isatest. If Einstein 
is right and the movements of the planets are due only to the 
sort of space they move in, then this space must affect everything 
alike. A ray of light, for instance, must behave just as a 
material body would do in moving through this space. It cannot 
do otherwise. Now part of the theory is that matter actually 
influences the space in its neighbourhood; it distorts it, as it were, 
from the Euclidean form. Near a great body like the sun space 
is considerably distorted. A ray of light passing near the sun 
and, consequently, moving through this distorted space, should 
deviate quite appreciably from the straight line. Kinstein’s 
theory predicts the amount of deflection, and, as we all know, a 
great expedition was sent out from England to test the theory 


VOLoLV——19 . 


1042 The Outline of Science 


by photographing the stars whose light passed near the sun when 
the sun was eclipsed. And the result confirmed Einstein. This 
verification of Einstein’s theory is a very striking one, for the 
result obtained could not have been predicted from any other 
theory. 

But this is not all. The motion of Mercury, the planet 
nearest the sun, presents peculiarities which cannot be accounted 
for by Newton’s Law of Gravitation. Great mathematicians had 
worried over this problem for generations, but no satisfactory 
explanation had ever been found. But the distorted space of 
Kinstein’s theory was found to supply a perfect explanation. 
This, again is a very striking confirmation of the theory. We 
must be content with this brief sketch of the theory; the details 
are too difficult for popular exposition. 

Einstein’s theory shows us that there is something in the 
nature of an ultimate entity in the universe, but it is impossible 
to say anything very intelligible about it. But a certain aspect of 
this entity has been picked out by the mind as being what we call 
matter. The mind, having done this, also partitions out a space 
and time in which this matter exists. It is not too much to say that 
the whole material universe has, in this sense, been created by the 
mind itself. 


BIBLIOGRAPHY 


Dinate, Relativity for All. 

Einstein, Relativity. 

NorpMANN, Einstein and the Universe. 

Scuuick, Space and Time in Contemporary Physics. 
Stosson, Easy Lessons in Einstein. 

Tuirrinc, The Ideas of Einstein’s Theory. 


XX XIII 


THE BIOLOGY OF THE SEASONS 


1043 


WWI? 


THE BIOLOGY OF THE SEASONS 


The Rhythm of Life 

EN and animals depend on green plants, and _ these 

depend on the sun. But according to the earth's 

seasonal relation to the sun we get varying amounts of 
heat and light. Thus the ratio of heat-supply in summer to that 
in winter is as 63 : 37. To the varying income of heat and light 
living creatures have had to adjust themselves, except in haunts 
like the Deep Sea, where there are practically no seasons. So the 
Biology of the Seasons has for its central task an inquiry into 
the ways in which the life of plants and animals is adapted to the 
external periodicities of Spring and Summer, Autumn and 
Winter. But the problem is complicated by the fact that within 
living creatures themselves there are constitutional rhythms or 
periodicities. HKveryone knows that after hard work he must rest 
and sleep and feed. A great expenditure of energy must be 
followed by a period of income. The essential processes of life, 
summed up in the word METABOLISM, consist of constructive, up- 
building, winding-up chemical activities (ANABOLISM), and of 
disruptive, down-breaking, running-down chemical activities 
(KaTABOLIsM), and there must be an alternation or see-saw 
between the two. Vital activity implies a two-fold process of 
waste and repair, discharge and restitution, activity and recupera- 
tion. Now the one predominates and again the other. Now there 
is storing and again there is work; now there is growing and again 


there is reproduction, As it is said in Ecclesiastes iii: 
1045 


1046 The Outline of Science 


To every thing a season . . . a time to break down, and a 
time to build up . . . a time to cast away stones, and a time 
to gather stones together; a time to embrace, and a time to 
refrain from embracing; a time to get, and a time to lose; 
a time to keep, and a time to cast away. 


There can be no doubt that deep-sea animals, living in 
monotonous uniformity—eternal night and eternal winter—have 
their internal rhythms, their see-saw between work and rest, their 
alternation of reproducing and vegetating. All living creatures 
are inherently predisposed to be rhythmic; their operations are 
regularly discontinuous. But the point is that the internal oscilla- 
tions have become adjusted to the external periodicities. We 
should have to sleep though there were no night, as in the Far 
North in summer, but we sleep better because of the night, which 
shuts off from our nervous system many of the messengers that 
are always rattling the knocker during the day. The central idea 
is that Life is rhythmic, and that it is punctuated by the seasons 
and by other external periodicities such as the tides. 


Ripple-marks of Growth 

Everyone has looked with pleasure at the well-sawn stem of 
a big tree, and counted the rings which register its age. We 
pause to think for a moment of one of the Big Trees or Sequoias 
of California, which showed 2,425 rings, and had therefore begun 
its existence 525 years before the Christian Era! (See p. 709.) 
But how is it possible to distinguish the annual increments of 
growth? Why do not the rings of wood simply coalesce? The 
reason is that the structure of the wood developed in summer is 
very different from that developed in autumn, and the alternation 
makes the lines of growth stand out clearly. 

In the same way we can read summer and winter in the 
concentric lines on the scales of a salmon and many another fish; 
and this can be corroborated by making a section of the otoliths, 
or ear-stones. All through organic nature there are what may 


The Biology of the Seasons 1047 


be called the ripple-marks of growth—the parallel lines on the 
scallop’s shell, on the tortoise’s scale, the rings on the rattlesnake’s 
rattle, and the zones within the spine of the sea-urchin. ‘There 
is a widespread self-registering of periodicities and pauses. 

The correlation between internal rhythms and external 
periodicities is sometimes very direct. Since photo-synthesis 
depends on the sunlight, green plants must be intensely active 
during the day and relatively restful at night. Similarly many 
plant-cells, such as simple Alge, feed during the day and divide 
at night. In other cases the correlation is more indirect and more 
subtle. Thus it is with striking regularity in October and 
November, when the moon is in her last quarter and the day 
before, that swarms of Palolo-worms occur in the coral-reefs 
of Samoa. 


Myriads of these worms crawl out tail foremost from the 
crevices they inhabit, and agitate themselves so violently that 
while the head end remains in the rock the posterior ends 
drop off and make the water “like vermicelli soup.” ‘These 
headless worm-bodies are laden with egg-cells and sperm- 
cells, and these are shed in countless millions in the water, 
so that fertilisation is quite secure. The swarming begins 
shortly before sunrise, and is mostly over in half an hour.’ 


There is much that is very interesting in this Palolo story. 
The swarming takes place so punctually that the natives are 
prepared for it, distinguishing the smaller October swarm from 
the larger one in November. The worms are eaten either .alive 
or baked, and are esteemed a great delicacy. The land-crabs also 
come down to the beach to get their share of the abundant jetsam. 
There is some subtle stimulus connected with the moonlight and 
the sunrise. There is also the very profuse sowing of the seed. 
But perhaps the most extraordinary thing is the evasion of the 
death-penalty which reproduction often involves to animals. 


*Thomson, The Wonder of Life, 1914, p. 71 


1048 The Outline of Science 


For the heads of the Palolo-worms remain in the fissures of the 
coral-reefs, and grow new bodies at their leisure. 

In some cases the external periodicity takes so strong a 
grip: of the constitution that the animal exhibits the correlated 
change even when the stimulus is not operative. This is well 
illustrated by the little green Planarian worm Convoluta, which 
is common on the flat sandy beach of some parts of Brittany. 
When the tide is out the worms come up in crowds and form 
green patches on the sand. When the tide returns, just as the 
first wave reaches them, they retire into shelter. But Bohn has 
demonstrated that in a quiet aquarium, away from all tidal in- 
fluence, the worms exhibit for some time the normal rhythms, 
ascending and descending, keeping time with the tides. The 
external periodicity has gripped their constitution for a time. 


I. THE BIOLOGY OF SPRING 


Spring is a time of renascence, when a fresh start is made 
after a period of rest. The seeds have been lying dormant in 
tne earth; processes of fermentation have been going on within, 
preparing the compact legacy of stored food; bacteria begin to 
work at the bursting envelopes; moisture seeps in; the seedlings 
emerge, and exhibit delicate movements in shoot and root. (See 
the article on Botany.) 

The buds which have rested through the winter, well 
wrapped up in tough bud-scales, begin to burst. That is to say, 
the warmth of the spring sunshine has activated the living mat- 
ter; the cells are dividing into intricate orderliness; the watery 
sap 1s ascending from the roots, or, it may be, from places where 
it has been stored within the stem. Like the seeds, the buds were 
formed in the abundance of the previous summer; like the seeds, 
the buds are adapted to contain much within a small and well- 
protected surface. The young leaves in the leaf-buds are often 
twisted in a close spiral, and when the shoot grows they show 


Photo: J. J. Ward. . 
ANNUAL RINGS OF GROWTH IN PINE-WOOD 


In spring, when the growth is energetic, the wood-elements are larger than those formed during the slower growth later in the 
year. The early wood is important in the ascent of water; the late wood is important in giving the stem rigidity. The appearance of 


the two kinds of wood—dark lines and lighter zones in the photogranh—makes it possible to compute the age of the tree. But thereis 
sometimes a midsummer ring, and some tropical trees show norings at all. 


Photo: John J. Ward. 


ONE OF THE EARLIEST FLOWERS OF SPRING 


Male and female catkins of the ‘‘Palm”’ or ‘‘Pussie’’ Willow. The branch on the left bears female flowers, and that on the right 
male flowers. The male and female catkins grow apart on distinct trees. The flowers are reduced to the essentials, the stamens in 
the male, the carpels in the female, rising from the axil of a bract. There are no petals orsepals. Yet the flowers are almost always 
pollinated by insects, though those of their relatives are pollinated by the wind. There are still wind-pollinated willows in Green- 
land, but this is just a straw which shows how the evolutionary wind has blown. Insects, such as hive-bees and honey-bees, are 
attracted to the catkins by the sweet scent and the nectar. 


The Biology of the Seasons 1049 


the same spiral loosened and drawn out. In the one case the 
spiral means close-packing, in the other case it obviates too much 
overlapping of leaf by leaf. In the flower-buds the parts of the 
flower are all lying in miniature, and when the spring comes with 
a rush the flowers are ready. Brehm speaks of the sudden trans- 


formation on the Asiatic steppes. 


From the apparently sterile earth herbaceous and bulbous 
growths shoot up; buds are unpacked, flowers unfold, and 
the steppe arrays itself in indescribable splendour. Bound- 
less tracts are gorgeous with tulips, yellow, dark red, white, 
white and red. It is true that they rise singly in twos and 
threes, but they are spread over the whole steppe-land.* 


The sudden reappearance of flowers, so that the desert quickly 
becomes a garden, is more intelligible when it is clearly under- 
stood that the flower-buds were made in the previous summer’s 
sunshine, and that there are stores of nutrition within the plant, 
especially when there is anything like a bulb or a corm or a root- 
stock, as there is so often in the flowers of the spring. 

Many of the early flowers are somewhat primitive, as we 
may see in the willow-catkins; many tend to be bud-like as if 
some slight check had occurred in the opening of the blossom; 
and perhaps we should expect something of the primitive and the 
bud-like in the first flowers of the year. We have just spoken 
of the resplendent tulips of the steppes, and everyone is familiar 
with the fine blue of such early flowers as hyacinth and iris, but 
on the whole the spring flowers tend to be light in colour, e.g. 
white and yellow, like snowdrop and celandine. This probably 
means that in the scantier sunshine the average spring flower has 
not the intensity of vital processes that sets in later in the year, 
when the colours certainly deepen. It may also be associated 
with the fact that not a few of the spring flowers are wind- 
pollinated, and that variations in the direction of bright colour 


*Brehm’s North Pole to Equator, 1896, p. 95. 


1050 The Outline of Science 


are not so likely to take grip in flowers that blossom at a time 
when insects are not much in evidence. 


Animals Reawaken 


There is a spring reawakening or renascence among animals 
as well as among plants. One of the most familiar sights is the 
queen humble-bee making for the willow-catkins to refresh her- 
self after a winter’s fast and to collect pollen and nectar for 
provisioning the cradles which she will soon fashion in her nest 
in the mossy bank. She has been resting in a sort of lethargy 
all through the winter, one of the few survivors, perhaps the only 
survivor, of last year’s large family. Of the scores, or even 
hundreds, that then crowded the nest, only the young queens 
survive. 

Many insects pass the winter, not in the adult state, but as 
cocoons or pupe. In sheltered recesses they have lain like 
mummies well protected by enswathing wrappings. They entered 
into their quiescent state as larve, e.g. caterpillars; they under- 
went at least a part of their great change or metamorphosis into 
a new style of bodily architecture; they reawaken in spring as 
winged adults, e.g. butterflies. 

Similarly, there is a reawakening of the snails, which have 
been lying sealed up in their shells in the heart of an old wall; 
and of the frogs, which have been dormant in a snug hole of the 
bank near the pond—mouth shut, nose shut, eyes shut, breathing 
through their skins and with their hearts beating feebly. The 
vigour of the males’ croaking and the rapidity with which the 
females proceed to deposit masses of spawn in the pool cannot be 
said to suggest any impairment of energies through the winter 
months. ‘Then there is the interesting reawakening of winter- 
sleepers, such as hedgehog and dormouse, marmot and bat. 

Spring is emphatically a time for young things—of seed- 
lings, buds, and young blossoms, of tadpoles, nestlings, and young 
lambs. There is a striking multiplication of minute organisms 


The Biology of the Seasons 1051 


in the waters of pond and lake, of estuary and sea. It is interest- 
ing to find in freshwater basins that there is often, as the result 
of the dying away of plants in autumn and winter, a production 
of chemical substances called “auxetics,”’ which later on promote 
the multiplication of cells, and, towards spring, an increasing 
quantity of certain other substances called “augmentors,” which 
give more “‘power to the elbow” of the first. ‘Thus out of death 
come the stimulants of the awakening of pond-life and lake-life 
in spring. A single Infusorian may be the ancestor of a million 
by the end of a week—of more if the spring is genial. As we 
have noted in another article, the water-fleas eat the infusorians, 
and fishes eat the water-fleas; and so the world goes round and on. 

One of the interests of spring is the repeopling of the fresh 
waters which seemed so empty through the winter. The fe- 
male gnat or mosquito spends the winter in hiding and makes 
in spring a floating raft of two or three hundred somewhat 
cigar-shaped eggs. From these there emerge larve which 
hang head-downwards from the surface film, or sink to the 
bottom of the pool and jerk themselves up again by vigorous 
strokes of their tail. They feed and grow and moult, and even- 
tually turn into pup of very different appearance, which rest 
head-upwards at the surface and do not eat at all. In three or 
four days the husk of the pupa splits and a winged gnat emerges, 
not without risk and difficulty. Many biological notes are struck. 
There are the adaptations of the gnat larve to living in the water 
and yet breathing dry air. There is the accumulation of reserves 
for a very vigorous short aerial life, mainly devoted to reproduc- 
tion. There is the prolific multiplication and the prodigious 
infantile mortality; and in spite of the latter there are clouds of 
survivors—fine food for some of the migrant birds returning to 
the North. And there is the interlinking with human life, for the 
mosquito which carries the malaria organism and infects man 
with it is Just a species of gnat. The pouring of a little paraffin 
on the pool makes a surface film which the mosquito larvee cannot 


1052 The Outline of Science 


grip, and so it is drowned—with consequent reduction of malaria. 
Then there are the small fishes that devour the mosquito larva— 
wheels within wheels. 

The gnat’s life-history occupies about a month, and there 
is a succession of generations through the summer. When this 
is contrasted with the long life of the May-fly, which may be 
sub-aquatie for three or four years, though aerial for only two 
or three days, or it may be only one, there emerges another 
biological idea—that a portion of the life-history may be long 
drawn out in one type and telescoped down in another, all in 
adaptation to different conditions of life. 

When we turn to the familiar development of the frog, 
which occupies about three months, we find a clear illustration of 


another biological idea—that of recapitulation. The individual 
tends to climb up its own genealogical tree. When it wriggles 
out from the protective sphere of jelly, the newly-hatched larva 
is little more than a very primitive vertebrate—limbless and 
gill-less, with eyes which have not yet reached the surface on their 
out-growing from the brain. When it is about a month old, the 
tadpole has a two-chambered heart, just as fishes have, and a 
very fish-like circulation. It is true that its gills are not like 
those of ordinary fishes, being “ectodermic”’ in origin, but they 
have their counterparts in the external gills of some old-fashioned 
fishes like the African Dipnoan, Protopterus. When it is about 
two months old and has got its limbs free, the tadpole begins to 
breathe with lungs as well as gills, just like the mud-fishes or 
Dipnoi. The individual development recapitulates in abbreviated 
form the evolution of the race, and yet from the very first the 
larval frog is an amphibian, not a fish. There is, for instance, 
no suggestion of scales. 

Some of the butterflies and moths that have wintered as 
adults emerge and pair in the spring, and thus arise the early 
caterpillars which are often a source of considerable anxiety to 
the gardener. The contrast between the worm-like caterpillar 


The Biology of the Seasons 1053 


and the winged butterfly is very striking—had we not become 
familiarised. A worm-like body, mouth-parts suited for biting, 
very diminutive antenne, simple eyes, three pairs of jointed, 
clawed legs, and five pairs of unjointed, unclawed, posterior 
appendages—everything as different as possible from the butter- 
fly. The crawling caterpillar is a voracious eater, the flying 
butterfly sips nectar daintily or sometimes fasts altogether. It is 
an antithesis—the antithesis between a nutritive and a reproduc- 
tive phase. The stores of nutritive material accumulated by the 
caterpillar make the butterfly possible. There can be little doubt 
that changes involved in the evolution of climates made it profit- 
able for the higher insects to have a long larval period interpo- 
lated between the egg and the adult. In the larval period 
reserves are accumulated, and at the end of the period, after full 
size has been attained, the great change or metamorphosis is 
initiated, completing itself in a quiescent pupa phase well suited 
for surviving the winter. But it is not easy to understand how 
the development which expressed certain hereditary qualities in 
building up a caterpillar should be able to reeommence on a new 
plan and express other hereditary qualities which make up the 
butterfly. 


The Story of Lampreys 


In the Severn and other southern rivers the sea-lampreys 
come up in the spring, and the spawning is over by the end of 
June. It is later further north. These lampreys are big crea- 
tures, as long as one’s arm and as thick as one’s wrist, very lithe 
and slippery. If the word “fish” is to mean anything, it cannot 
be applied to lampreys, for they are jawless, limbless, and scale- 
less, and they have an unpaired nostril and peculiar gill-pouches, 
very different from the gills of ordinary fishes. They are 
representatives of primitive backboned animals, far below the 
level of true fishes, for there is a big anatomical gulf between 
animals without jaws and those that have them—between Cyclo- 


1054 The Outline of Science 


stomes and Gnathostomes, if we use the zoological language. 
Like most archaic animals, lampreys are _ extraordinarily 
interesting. 

The parents usually choose a briskly flowing stretch of the 
river, and they clear a nesting site by removing the stones in their 
suctorial mouths. If a stone is too heavy for one, the pair will 
tackle it! The stones are piled in a sort of breakwater on the 
up-side of the chosen spot and in a dam on the down-side, so 
that the eggs are less likely to be washed down-stream. In the 
shelter of the stone nest the eggs are laid, and the development is 
rapid; a rather interesting point, for the larval period is long- 
drawn-out. The young ones hatch out in about a fortnight, and 
in a month or so, when only half an inch long, they leave the nest 
and seek quietly flowing water. They wallow in the sand or 
mud, and feed on other water-babies. | They grow out into what 
country boys call “niners,” often confused with young eels, with 
which, of course, they have nothing whatever to do. An interesting 
detail, significant in its adaptiveness, is that the skin of the young 
lamprey secretes a digestive Juice, making short work of the 
bacteria which abound in rather stagnant water. The name 
“niners,” or “nine-eyes,” is rather difficult to explain, for the 
larve are blind. There are eight gill-openings, however, and 
there is the place where the eye will eventually emerge, so these 
make nine—the “nine-eyes”’ of rustic Natural History! 

After three or four years of rather monotonous youth, the 
niners begin to grow up. They undergo a remarkable structural 
change, putting off their juvenile characters, such as their 
horseshoe shaped mouth, and putting on adult characters, such 
as clearly exposed eyes. The change usually takes place in the 
autumn. at 

There are species of lamprey that remain in fresh water, 
but the large species we have been studying (Petromyzon 
marinus) spends a considerable part of its life in the sea. After 
two or three years (the number is uncertain) spent in the sea in 


FIG. I.—HORSE-CHESTNUT BEGIN- 
NING TO BURST ITS BUD-SCALES ON 
MARCH 25 


These bud-scales have protected the 
bud since it was formed—during the 
previous summer. They are water- 
proof and bad conductors. They are 
burst because of the pressure of the 
growth in the young leaves within. 


aets 


Hil Gree OL CULM DAY sb) EAST PATR 
OF BUD-SCALES GIVE WAY 


As the bud elongates it is interesting to 
see that there is a gradual transition be- 
tween the bud-scales and the leaves. For 
the scales are leaf-bases specialised for 
protective function. 


FIG. 3.—TENTH DAY, TH FIRST 
PAIR OF LEAVES ARE ALMOST 
READY TO OPEN OUT THEIR 

LEAFLETS 


The leaves arise opposite one another 
and each is palmate, that is to say, the 
leaflets spread out like the fingers from 
the palm of the hand. 


FIG. 4..-THE BRANCH SHOWN IN FIG. I IS HERE SEEN 
AS IT APPEARED ON MAY 3 


The palmate leaves are in their resting position, suffering a 
little from the drought. The beautiful white candelabra-like 
inflorescence has also appeared. 


Photo: J. J. Ward. 


FIG. 5.—ON JULY I7 THREE FRUITS HAVE BEGUN TO 
FORM AT THE BASE OF THE FLOWERING BRANCH 


The seeds have a bitter taste, but they are rich in starch. 
They are given in Turkey to broken-winded horses, and 
reduced to powder they serve as soap. 


FIG. 6.—BY SEPTEMBER I7 THE FRUITS HAD GROWN 
LARGE, WITH PRICKLY COATS 


The Biology of the Seasons 1055 


active predatory life—gripping fishes and rasping holes in their 
skin with a very effective toothed piston—the big Marine Lam- 
preys return to the rivers to make their stone nests and spawn. 
It is a remarkable fact that they die after spawning, as eels seem 
to do. We have found the strong muscular body floating spent 
in the shallows of the river. As in the case of the delicate May- 
flies, so with these big lusty lampreys, the giving rise to new lives 


means the end of the old. 


The Eel-Fare 

It is in spring that the young eels or “elvers” come up the 
rivers from the sea in countless crowds. They are about 214 
inches in length, and like a very stout knitting needle in girth. 
They hug the banks but move persistently up-stream as long as 
the daylight lasts. When the sun goes down behind the hills 
they snuggle under stones and lie quiet till dawn. Their persist- 
ent migration illustrates in part an instinctive impulse, which 
does not work except in the light, and in part a “tropism,” for the 
elvers automatically adjust their bodies so that the pressure of 
the stream plays equally on each side. The story of the eel has 
been referred to already in the article on THE Haunts or LIFE; 
it must suffice to say that the elvers are already a year and a 
half old, that they spent their previous juvenile period as trans- 
parent knife-blade-like creatures (Leptocephali) near the sur- 
face of the Open Sea, that they go up-stream to quiet reaches and 
to ponds, and that the successful survivors return to the sea as 
big eels in 5-8 years. 


The Return of the Birds 

One of the pleasantest changes in spring is the return of 
the migratory birds which have been wintering in the south— 
birds like swallow and swift, cuckoo and nightingale (see article 
Birps). In many cases the adult males arrive first, and some- 
times, as in the case of warblers, they choose a “territory” before 


1056 The Outline of Science 


their mates appear on the scene. The immature youngsters are 
the last to come. There is often great punctuality in the arrival 
of these summer visitors, as the puffins on the cliffs well illustrate; 
and another striking feature is that a bird, e.g. swift or swallow, 
may return to its precise nesting-place of the previous year. 
The silence of winter is soon broken; the country is full of 
singing birds. 


II. THE BIOLOGY OF SUMMER 


Summer is the time of maximum output and income of 
energy, when the fires of life not only burn brightest but begin to 
be banked up for another year. For it is characteristic of living 
creatures that they are able to accumulate energy acceleratively, 
that they are able to store. 


Intense Activities of Summer 


The most important activity of summer is the quietest of 
all—the manufacture of sugar and starch and still more valuable 
materials in the green leaves. ‘The result is the accumulation of 
a great wealth of food—in a wheat field, for instance. Some of 
this goes to account of growth, e.g. in forming the buds for the 
next year; some of it is stored in root and stem and seed; some of 
the sugar is drafted into the flower to overflow as nectar and to 
fill the fruit with succulence; and no small part of it is immedi- 
ately devoured by animals, passing into a fresh incarnation. 

Summer is distinctly a flowering time, as spring of leafing; 
and as the days grow warmer and brighter the floral colours grow 
in intensity. There was more than a grain of truth in the old 
meteorologist’s suggestion that the annual succession of colours 
in flowers corresponds on the whole to that of the rainbow. 

If industry means the transformation of matter and energy 
from one form to some other form, then green plants are very 
industrious, and the same is true of the bees which are visiting 


The Biology of the Seasons 1057 


the flowers and transforming the nectar of the blossoms into the 
honey of the honeycomb. As is indicated in the article on Botany, 
it is very interesting to inquire into the ways in which insects are 
attracted to the blossoms, whether by brightly coloured flags that 
catch the eye, or by fragrance appealing to the sense of smell, or 
by a recollection of a previous feast of nectar. It is important to 
notice, as Aristotle observed two thousand years ago, that — 


a bee, on every expedition, does not pass from one kind of 
plant to another, but confines itself to a single kind—for 
instance, to violets—and does not change until it has first 
returned to the hive. 


There are, indeed, exceptions, but what Aristotle noted is gen- 
erally true, and the habit makes it more certain that the fertilising 
pollen will be scattered in an appropriate way, and not at ran- 
dom. Many biological notes are sounded, e.g. the value of the 
cross-fertilisation made possible by the most important linkage 
in the world (see article on INTER-RELATIONS), and the neat 
adaptation of insect to flower and of flower to insect. ‘They fit 
like hand and glove. 


Industries of Animals 

The twofold business of animal life is caring for self and 
caring for others, and both may involve great industry. That 
is to say, things are made or moved, captured and stored, or 
changed from one form to another. When we think of an ant- 
hill, a piece of honeycomb, a bird’s nest, a badger’s burrow, we 
must admit that animals are often very industrious. Consider 
the business of hwnting—the otter hunts alone, the wolves in 
winter hunt in packs; the sparrow-hawk hunts by day and the 
barn-owl by night; some big spiders pounce on their prey, most 
make snares and webs; the grub of the tiger-beetle makes a trap 
and the larval ant-lion a pitfall; the stoat pursues the rabbit with 
all its speed but the cat stalks the mouse with a hardly perceptible 


VOL. IV—I3 


1058 The Outline of Science 


approach. As to fishing, the pelicans work in companies, the 
heron fishes alone; the dipper walks about and even uses its 
wings under water, and the osprey catches the trout in its talons. 
As to shepherding, several species of ants treat green-flies, or 
Aphides, as if they were cows, and even look after the young. 
As to farming, the Agricultural Ant of Texas weeds small 
circular patches, leaving only the needle-grass, the seeds of which 
are much esteemed. Both true ants and “white ants” (see the 
article on THE INsEct WoRLD) grow certain Fungi, from which 
they obtain an important part of their food. ‘The main use of the 
leaves which the Leaf-Cutting Ants collect seems to be to form, 
after they have been chewed, a medium on which the prized 
Fungus will grow. When the queen Leaf-Cutter founds a new 
colony she brings with her a minute pill of the Fungus, which 
forms the starting-point of a fresh growth. As to storing, we 
think of the squirrel’s caches of nuts, the ants’ granary, the 
hive-bees’ honey, the digger-wasps’ paralysed caterpillars. Then 
there is the making of shelters and nests and burrows. A climax 
along one line is the great termitary exceeding a man’s height, 
built of salivated earth and often with internal furnishings of 
chewed wood. A climax on another line is the hanging paper 
house of the wasp, with one story suspended from another, and 
all surrounded by wind-proof and water-proof walls. There is 
no doubt as to animal industries. 


Birds’ Nests 

Without trespassing on the article on Brrps, we may 
emphasise what is important biologically in connection with nest- 
making. It is in great part an instinctive activity, but intelli- 
gent adjustment to peculiar conditions and materials is often 
detected. The kind of nest is often very specific; thus the black- 
bird and the thrush, which are first cousins, build very different 
nests. There is an inclined plane from no nest at all, as in 
guillemots, to elaborate nests like those of weaver-birds and the 


The Biology of the Seasons 1059 


wren. The evolution of nests is to be linked up with the facts 
that it is always dangerous to lay eggs on the ground; that the 
development of embryo and nestling alike often demands a 
temperature which cannot be attained without the use of non- 
conducting material round about; that it is important that the 
parent bird be made comfortable during the long patience of 
brooding; that it makes the business of feeding the young easier; 
and that it is often essential that the eggs and the nestlings should 
be hidden from hungry eyes, and the young birds sheltered from 
the glare of the sun and from the danger of tumbling out. 
Finally, we find in the study of birds’ nests many an eloquent 
reminder that in the struggle for existence the evolution of 
parental care may pay just as well as the evolution of sharp 
beak and strong talons. Professor MacGillivray counted 2,379 
feathers in the beautiful nest of the Long-Tailed Tit. 


Parental Care 

The parental care so marked in birds is widespread through 
the whole kingdom of animals, and it is, on the whole, most 
characteristic of summer. Let us select three or four pictures. 


We sit down among the heather, and as we peer into the 
jungle round about we often see a mother spider moving 
swiftly and skilfully with a tiny silken bag on her breast. 
This is a “cocoon” containing eggs, and after a while young 
spiders. ‘The mother seems to clutch it underneath her body 
with the help of the bases of her legs; but it is sometimes 
bound to her by silken threads. She looks as if she thought 
a lot of it, though we do not suppose that she thinks as we 
count thinking. But she resists if you try to take it away; 
and if you pull it off and place it at a little distance she seeks 
for it carefully—by scent, it seems, for she is very short- 
sighted. It is her family that she is carrying about till the 
young ones come out and run hither and thither of them- 
selves, just like miniatures of their mother. Other spiders 
make silken nests on the heather, or in crevices among stones 


1060 The Outline of Science 


and bark; others hide their beautiful cocoons—white, pink, 
or greenish—in shelters made of bramble-leaves bound to- 
gether with silk; the water-spider rears her family in a 
diving-bell of silk on the floor of a pool; the trap-door spider 
sinks a long shaft in the ground.* 


In early summer the male Three-Spined Stickleback, con- 
spicuous in red and green, makes a barrel-shaped nest in a shore 
pool or in a freshwater pond. Pieces of seaweed or of freshwater 
plants are glued together with sticky threads from the kidneys, 
and a cavity is made in the middle. A female is induced to enter 
the nest, where she lays a few eggs. When she has gone, another 
and another does the same, for the stickleback is polygamous. 
Over the nest the male then mounts guard, driving away other 
sticklebacks and much larger fishes. He is extremely pugna- 
cious. When the young ones hatch out, the nest is partly picked 
to pieces, but the male still takes solicitous charge of the family. 
If a youngster strays, it is retrieved by the father fish and carried 
home in his mouth. 

Wasps play an important part in the economy of nature 
by keeping down the numbers of injurious insects.. Many of 
them kill not only for themselves but for their larve. Among the 
Digger-Wasps, some of which make tunnels in dry banks by 
the roadside, the mother places paralysed caterpillars and the 
like beside her laid eggs, so that there is fresh meat for the grubs 
when these hatch out. By that time the mother-wasps have died 
for they never see the reward of their labours. It is probable 
that the habit was established when the tenure of the parent’s 
life was longer. In some other predatory wasps, such as 
the African Fury-Wasps, the mother brings freshly stung insects 
day by day to her offspring—there is sometimes only one—so 
that there is more of a personal touch here. In a third set of 
predatory wasps, the mother kills the insect right away, chews 
it into a mince, and gives this to her offspring, receiving in return 


*Thomson, Nature all the Year Round, 1920, p. 45. 


Photo: J. J. Ward. 
SNAILS ‘‘LAID UP’’ FOR THE WINTER ON A SHELTERED WALL 


The mouth of the shell is closed by a non-conducting lid of hardened slime and lime (the epiphragm), through which an interchange of 
gases takes place. The life of the snail sinks to a minimum. 


or 


Reproduced by permission from ‘‘ The Wonders of Instinct,”’ by J. H. Fabre. 
INSECTS AT REST 


Bees and wasps ‘‘asleep,’’ fastened stiffly to the stem by the clinching of their mandibles. 


t 


Photo: J.J. Ward. 


TWO ANTS SHEPHERDING GREEN-FLIES OR 


APHIDES, WHICH THEY USE AS “cows,” 
LICKING UP THE ‘‘HONEY-DEW’’ WHICH IS 
SECRETED 


The ants sometime take the aphides underground in 
autumn, and they may even look after the eggs which the 
aphides lay. The linkage approaches domestication. 


Photo: J. J. Ward. 


young spiders. 


HUNTING SPIDER (Dolomedes mirabilis) CARRYING A SILKEN 


EGG-COCOON 


The cocoon of a spider is very different from the cocoon which some caterpillars spin 
around themselves when the time comes for metamorphosis. 
spider's cocoon is made by the mother as a bag to contain the eggs and, by and by, the 
It is a portable cradle or nest. Many spiders hide it in some suitable 


corner; others carry it about below the body. 


Both are silken, but the 


The Biology of the Seasons 1061 


a drop of overflowing juice from the grub’s mouth—an elixir 
that seems greatly appreciated. 

The salient biological fact in summer is, we think, the 
extraordinary activity at various levels—vegetative, instinctive, 
and intelligent. The activity is swayed by the twin impulses of 
Hunger and Love. There is eager endeavour after individual 
well-being, and there is not less careful effort which secures the 
welfare of the young. The intensity of life sometimes goes too 
far, as the worker-bee illustrates in its very short life and in the 
demonstrated fact that a certain number of its brain-cells are 
always becoming over-fatigued and going out of gear. Another 
illustration of the tendency to overdo things may be found in 
the “summer-sleep” or estivation of some animals in warm 


countries. Thus the tenrec (Centetes) of Madagascar—an 
earthworm-eating Insectivore—relapses in summer into a state 
hardly distinguishable from hibernation. We may notice in 
passing that there are many peculiar features in this type: thus, 
some of its dorsal hairs have turned into spines, and as the animal 
cannot roll itself up, like its distant relative the hedgehog, it 
dashes them with some force into the skin of an assailant; and, 
again, it has been reckoned as the most prolific of mammals, for 
it is reported to have had twenty-one young ones in a litter. But 


this is by the way. The keynote of summer is activity! 


III. THE BIOLOGY OF AUTUMN 


Autumn Fruits 

Although autumn is the time when the tide of the year 
turns, a dominant biological impression is that of the abundance 
of life. We get that impression in the orchard and in hedgerow 
alike when we observe the abundance of fruits. Leafing in 
spring, flowering in summer, fruiting in autumn, resting in 
winter, such is the plant’s normal life-story. A fruit consists of 
the full-grown seed-box or seed-boxes, often with accessories in 


1062 The Outline of Science 


the form of any parts of the flower or flower-stalk that may 
persist after the pollination. When the insect visitors have done 
their work and the possible seeds or ovules have become real seeds 
with a developing egg-cell within, the nectaries are closed, and 
the surplus sugar may be drafted into the fruit, as in stone-fruits 
and berries. But there are, of course, many kinds of fruits— 
pods, capsules, nutlets, nuts—which are not succulent. What 
are the chief uses of fruits to the plants that bear them? 

The essential part of the answer to this simple question is 
that the use of the fruit is racial, not individual. ‘They protect 
the seeds and they may help to scatter them, e.g. when they dry 
and break, like the withering leaves they are, or when with their 
dead roughnesses they adhere to passing animals. In other cases 
the succulence and fine colours attract hungry birds and fruit- 
eating mammals. At first glance it does not seem clear why 
being eaten should be of great service, but the point is that the 
seeds inside the fruit are often left undigested and are sown far 
and wide by the creatures that devoured the fruits. Seeds are 
rich in proteins; fruits have little of these valuable nitrogenous 
carbon compounds. ‘They may have sugar, but sugar is simple 
compared with proteins, and is non-nitrogenous. Supposing 
the seeds are not eaten, it requires 144 lb. of grapes, 2 Ib. of 
strawberries, 21% lb. of apples, and 4 Ib. of pears to furnish as 
much protein as there is in a hen’s egg or a small handful of peas. 
The significance of this is that what is spent in the fruit is lost, 
but what is stored in the seed is legacy. 


The Scattering of Seeds 


When man is harvesting, nature is scattering seeds. On a 
genial autumn day the pods of the gorse may be heard bursting; 
many capsules crack less violently, sometimes helped by seed- 
eating birds; rough-coated fruits (which may be practically 
equivalent to seeds) adhere to furry animals like rabbits and fall 
off by and by; others, like dandelion-down and thistledown, are 


The Biology of the Seasons 1063 


wafted about singly by the wind, and the plumose nutlets of the 
Clematis or Traveller’s Joy are entangled in long lines, which 
float off with a beautiful wavy motion, “like silver serpents in 
the air.” Some birds digest the seeds they eat, but many fruit- 
eating birds pass out the seeds undigested and none the worse 
for their sojourn in the food-canal. Other seeds, as is noted in 
the article on INTER-RELATIONS, are distributed in the clodlets 
which accumulate on birds’ feet and are washed off far away. 
There are many other methods of seed-scattering: thus the pea- 
nut pokes its pod into the earth, and the beautiful Ivy-leaved 
Toadflax on the wall pushes its box-fruit into a cranny, both 
behaving almost like animals, though the whole process may be 
explained in terms of automatic “tropisms.” 

The seed-scattering in autumn impresses us with the abun- 
dance of life, but the other side of the picture is the abundance 
of death—the chances against the germination of the seed are so 
enormous. ‘Tennyson wrote with reference to nature’s prodi- 
gality: “Of fifty seeds, she often brings but one to bear”; and he 
afterwards thought that he should have written “myriad”’ instead 
of “fifty.” Darwin noted that the common Spotted Orchis may 
have 30 seed-boxes, each with 6,200 seeds. If we allow 400 bad 
seeds to each box there would be 174,000 seeds from one plant. 
These would cover an acre; the grandchildren would cover the 
Island of Anglesey; the great-grandchildren the whole land- 
surface of the globe. Such things do not happen, the chances 
against the success of the seeds are so great, as we are told in 
the immortal parable. ‘There is enormous mortality and apparent 
wastage, but part of the elimination is discriminate, and this 
winnowing, singling, sifting, which we call Natural Selection, 
is one of the secrets of progress. 


Withering Leaves 


All through the summer the green leaves have been the seat 
of intense activity, but this wanes in autumn, and they wither. 


1064 The Outline of Science 


They have begun to suffer from the wear and tear of living; the 
furnishings of the cell laboratories are becoming worn. More- 
over, it is well that the leaves should die, reducing the exposed 
surface from which water is given off, for as the soil gets colder 
it becomes more difficult for the roots to keep up the supply. 

But before the leaves fall off they surrender all their useful 
material to the plant that bore them. There is a passage 
of sugar, green-pigment, and more complex materials—even 
living matter itself—into the stem and root. ‘There is almost 
nothing left in the withered leaf but ashes—and_ beauty. 
When the chlorophyll recedes it leaves yellow grains behind 
it, and the tree is crowned with gold. Often there appear 
special waste-pigments, such as anthocyan (also occurring in 
flowers and fruits) which give the leaves of bramble, vine, and 
Virginia Creeper their autumnal splendour. In various ways 
a weak line is established at the base of the leaf where it joins 
the twig. To the inside of this a corky partition grows across, 
which helps in the actual separation and forms a protective scar. 
The windy day comes and the leaves fall in thousands—to enrich 
the earth as they enriched the tree. 


The Work of Earth-worms 

It is in autumn that we see most of the work of earth-worms, 
dragging leaves into their burrows and thereby making vegetable 
mould, covering the surface with their castings of fine earth 
ground to powder in their gizzards. With their burrowing, 
bruising, and burying they have made most of the fertile soil of 
the world. ‘This has been dealt with fully elsewhere (see p. 644). 


Flights of Gossamer 

Almost at any time of year there may be a shower of 
gossamer, but the characteristic time is in autumn—naturally 
enough, for the biological significance of the occurrence is as a 
spreading out of small spiders from a crowded area, and the 


Photo: J. J. Ward. 
THE EXPLOSION OF THE BROOM PODS 
The seed-pods of the Broom ripen in August, and change 
from green to black. In the heat of the sun they burst open 
with a crackle. The two valves twist into a spiral and the 
seeds are jerked out to a distance of several feet. This is very 
effective, but there is no vitality init. The explosion is due to 


the unequal shrinking of two layers of woody cells in the wall of 
the pod. Itisa mechanical mode of seed-scattering. 


tit 


Z 


Bea sinvaeenaneNe ‘a aes 


Fho.o: J. J. Ward. 


FRUITING HEAD OF THE WILD TEASEL (Dipsacus 

sylvestris), WHICH JERKS OUT THE FRUITS 

MECHANICALLY, BY THE UNEQUAL SHRINKAGE OF 
THE SPRINGY BRACTS 


The hard recurved bracts of the cultivated Fuller’s Teasel 


(Dipsacus fullonum) are used for raising a nap on woollen 
cloth. 


ee 


2 


WINTER 


The trees are leafless and the above-water parts of the aquatic plants have died away, leaving in most cases only the roots which are 
fixed in the mud. 


(See next photograph.) 


The Biology of the Seasons 1065 


crowding is greatest after the abundance of summer. What 
happens is certainly remarkable. 

Certain small spiders, especially when they are young, 
mount, on a breezy morning, on posts and paling, or on the top 
of tall herbs. They stand with their head to the wind and allow 
threads of silk—often four—to float out from their spinnerets. 
The multiple jets of liquid silk harden instantaneously on ex- 
posure to the air, and the wind begins to tug them. Then the 
small spider lets itself go from its perch, and, usually turning 
upside down, allows itself to be carried on the wings of the wind, 
supported by the silken floats. Reference has been made to this 
in another article, and it is enough to say that when thousands 
of spiders make their aerial journeys on a suitable morning, and 
eventually sink to earth, the threads may cover great stretches of 
links and meadow, field and hedgerow, and there is a “shower of 
gossamer.” ‘The wingless aeronauts or balloonists may be borne 
for many miles—sometimes far out to sea—and except in the 
last case, they are often successful in their passive migration. 


Preparations for Winter 

There is much in the biology of autumn that may be summed 
up in the idea of preparing for the hard times of winter. There 
is much storing on the part of plants; there is much on the part 
of animals, both inside their bodies and outside. The bud gets its 
hard, sometimes varnished, protective scales; the animal may get 
a thicker coat of fur. In the fall of the leaf there is a particularly 
striking example of a widespread tendency to sacrifice the more 
vulnerable parts and entrench. The birds we call “summer 
visitors’ make their way southwards to more hospitable shores, 
and there are other movements besides true migration which may 
take place in autumn. A true migration is a seasonal mass move- 
ment from a crowded breeding-place to a place for recuperation 
—typically the winter-quarters, whence there is normally a 
return of the survivors the following year. Of course, there are 


1066 The Outline of Science 


exceptional cases, like the migration of the freshwater eels to the 
Deep Sea, where they seem to die after spawning; but in 
ordinary cases the migration is a periodic mass movement with 


a return journey. 


The Story of the Lemmings 

It seems warrantable to distinguish from true migration 
such mass movements as lemmings sometimes illustrate in the 
autumn. Brehm tells us how a warm summer increases their 


numbers past computing and past supporting. 


Scarcity of food begins to be felt, and their comfortable life 
comes to an end in panic. Their fearless bold demeanour 
gives place to a general uneasiness, and soon a mad anxiety 
for the future takes possession of them. Then they assemble 
together and begin to migrate. The same impulse animates 
many simultaneously, and from them it spreads to others; 
the swarms become armies; they arrange themselves in ranks 
and a living stream flows like running water from the heights 
to the low grounds. All hurry on in a definite direction, 
but this often changes according to locality and circum- 
stances. Gradually long trains are formed in which lem- 
ming follows lemming so closely that the head of one seems 
to rest on the back of the one in front of it; and the continu- 
ous tread of the light little creatures hollows out paths deep 
enough to be visible from a long distance in the mossy 
carpet of the tundra. The longer the march lasts the greater 
becomes the haste of the wandering lemmings. Eagerly 
they fall upon the plants on and about their path, and devour 
whatever is edible; but their huge numbers impoverish even a 
fresh district in a few hours, and though a few may pick up 
a little food nothing is left for those behind; the hunger in- 
creases every minute, and the speed of the march quickens 
in proportion; every obstacle seems surmountable, every 
danger trifling, and thousands rush on to death. If men 
come in their way they run between their legs; they face 
ravens and other strong birds of prey defiantly; they gnaw 


The Biology of the Seasons 1067 


through haystacks, climb over mountains and rocks, swim 
across rivers, and even across broad lakes, arms of the sea, 
and fjords. A hostile company follows in their wake: wolves 
and foxes, gluttons, martens and weasels, the ravenous dogs 
of the Lapps and Samoyedes, eagles, buzzards, and snowy 
owls, ravens and hoodie crows fatten on the innumerable 
victims which they capture without trouble from the moving 
army; gulls and fishes feast on those which swim across the 
water. Diseases and epidemics are not awanting, and prob- 
ably destroy more of the lemmings than all their enemies put 
together. Thousands of carcases lie rotting on the wayside, 
thousands are carried away by the waves." 


In some cases the remnant of the army reaches the sea, and this 
also the lemmings seek to cross, obedient to the instinctive com- 
mand engrained in their dull-witted smooth brains to go straight 
on at all costs. The waves of the North Sea or the Baltic sweep 
over them, and the march of the lemmings is ended, and their 
population problem solved. 


IV. THE BIOLOGY OF WINTER 


Winter is the low-tide of the year. Fundamentally because 
the reduced income of heat slows the chemical processes which 
living involves, and because the reduced income of light checks 
the manufacturing activity of the green leaves. But there are 
other reasons. ‘The low temperature makes it imperative that 
many of the delicate structures of plants and animals should be 
shed or absorbed, else the whole creature will be fatally in- 
jured; the hardness of the frost-bound earth makes it necessary 
that many animals should lie low; in the scarcity and the storms 
and the short days there are reasons enough for the migration of 
birds to the south. Behind all this there is the physiological need 
for rest after toil. 


‘Brehm’s North Pole to Equator. 


1068 The Outline of Science 


Winter Whiteness 

Perhaps the most interesting aspect of the Biology of 
Winter is the variety of solutions that different creatures offer 
when face to face with the same problem—the cold, the scarcity, 
and the storms. A neat solution is to be found in the change to 
whiteness which occurs in ptarmigan and mountain hare, in the 
Hudson’s Bay lemming and the Arctic fox, and in the common 
brown stoat which becomes the pure white ermine. ‘The blanch- 
ing is usually brought about by growing a new unpigmented 
suit, though there is sometimes a removal of the pigment from 
individual hairs. In the new-grown white hair or feather, and in 
a hair that has turned white, the place of the pigment is taken 
by gas vacuoles, from the surfaces of which the light is so per- 
fectly reflected that the hair or feather appears white—just like 
foam or snow. Many northern creatures, such as polar bear, 
white whale, Iceland falcon, and snowy owl, are more or less 
white all the year round. In these cases the whiteness is perma- 
nent, in the other cases it is periodic. In all cases, no doubt, a 
constitutional predisposition to the suppression of pigment has 
been established, but it is probable that the low temperature is 
the immediate condition of the non-appearance of the pigment. 
We must keep in mind the case of the wan newt called Proteus, 
from the Dalmatian Caves, which is always pigmentless in the 
darkness, but rapidly develops pigment when kept in the light. 
Similarly, the stoat sometimes remains a stoat, e.g. in the South 
of England, or, somewhat mysteriously, in individual cases. We 
do not know enough as yet to say how far the whiteness of the 
winter suit expresses an engrained racial periodicity not to form 
hair-pigment in the fall of the year, and how far the whiteness 
means that the cold has directly and individually affected the 
chemical routine of the body and the circulation in the skin. We 
await more facts. 

When we almost tread upon the white ptarmigan among the 
snow on the high hills, we are inclined to lay considerable em- 


The Biology of the Seasons 1069 


phasis on the protective value of the whiteness, which gives the 
bird a garment of invisibility. We should be slow to reject this 
interpretation, but suspicion rises in our mind when we see how 
conspicuous the mountain hare often is when there is no back- 
ground of snow. We are also aware that the stoat has almost no 
enemies from which it may escape by turning into a white ermine, 
and if it be said that the elusive carnivore is enabled to slink on its 
prey 
be rephed that the ermine is conspicuousness itself when the 


say a ptarmigan or a grouse—among the snow, it may 


surroundings are not white. In short, there must be some deeper 
significance in the periodic whiteness of ptarmigan and ermine, 
and in the permanent whiteness of snowy owl and_ polar 
bear. The answer to the biological riddle is that for a warm- 
blooded animal in very cold surroundings the most economical 
dress is white, for it loses least of the precious animal heat. It is 
physiologically the fittest dress because it conserves the warmth 
of the body which enables the chemical processes to go on quickly 
and smoothly. In very hot surroundings a white dress is again the 
best, for it absorbs less than other colours would of the external 
heat. 


Lying Low 

Another way of meeting the winter is to sink into lethargy, 
lying low and saying nothing. When there is no income, the 
only chance is to have no expenditure—or almost none. Thus 
the snail closes the mouth of its shell with a lid of hardened lime 
and slime, and, seeking the recesses of an old wall, lies inert 
through the cold months, not without some loss of weight and 
some degeneration in its tissues. When the outside temperature 
is near the freezing-point the heart of the garden snail may beat 
only four times a minute instead of the forty times observed in 
summer. It is hardly a modus vivendi (a way of living) that this 
snail has adopted, but it is a way of not dying; and that is always 
something. The same kind of lethargy is to be seen in the 


1070 The Outline of Science 


chrysalids of moths and butterflies, which often remain hidden 
away during the winter months, in many ways like the seeds of 
plants. But it must be remembered that in both cases changes 
may be going on—especially as the severity of winter begins to 
yield before the approach of spring. 

The full-grown frog feeds on insects and grubs, on earth- 
worms and slugs; but these are not readily available in the winter. 
So the frog snuggles into a hole in the bank, or up a disused 
drain-pipe, or even into the mud (though this is rare), and sinks 
into a winter torpor, which must not be confused with the true 
hibernation restricted to a few mammals. Similarly there are 
tortoises and terrapins that bury themselves in the dry ground 
or in the wet mud, and lie quiet all the winter through. In some 
kinds of tortoises the winter torpor does not set in if they are 
kept in artificially heated quarters, and it is interesting to learn 
that this disturbance of the natural rhythm sometimes upsets the 
constitution in rather subtle ways. Another instance of lethargy 
may be found in the limbless lizards, or slow-worms, which coil 
up together—sometimes a dozen of them—in a mossy bank; and 
a great tangle of adders is sometimes found in the recesses of a 
cairn or haystack. In cold-blooded animals, such as reptiles, 
amphibians, and fishes, the temperature of the body tends to 
approximate to that of their immediate surroundings; hence the 
advantage of a confined space or blanketed nook, which is a 
little warmer than the open. The body may become stiff with- 
out fatal results, but if the heart should be actually frozen 
there is no recovery. We cannot help wondering that survi- 
val is so frequent, especially in cases where the normal life 
is intensely active. It is not so difficult to understand survival 
when an insect spends the winter in’ a_ well-wrapped-up 
quiescent pupa state; but we have to bear in mind cases like 
the full-grown queen wasp or hornet in the crevice of an old 


tree, or the full-grown queen humble-bee in a hole in a mossy 


bank. 


Photos: S. Leonard Bastin. 


SUMMER 


The trees are in full leaf and the water plants show 


shoots 


and leaves rising 


out of the water. 


Barner | 


Photo: J. J. Ward. 


THE BLADDERWORT OR UTRICULARIA 


A submerged aquatic plant which traps tiny water animals, such as crustaceans, in its 
‘‘bladders,’’ which appear to be transformed parts of leaves. The ¢ Bladderwort has no roots. 
Beautiful yellow flowers, which appear but once in several years, rise above the water. The 
terminal buds, heavy with reserves, sink to the bottom in autumn, and rise again, lightened 
of their stores, in spring—starting new Bladderworts. 


The Biology of the Seasons 1071 


Winter Sleep 

In the article on MAmmats there is some discussion of true 
hibernation, as seen in hedgehog and marmot, dormouse and 
bat. A brief reference must therefore suffice. A few mam- 
mals, such as those just mentioned, have some imperfection 
in their warm-bloodedness, that is in the power (confined 
to birds and mammals) of adjusting the production of heat 
and the loss of heat so that the temperature of the body 
remains constant. The hibernators are those mammals that can- 
not balance their books as regards heat; when the cold weather 
sets in they give up a hopeless struggle, in obedience to an en- 
grained constitutional rhythm; they betake themselves instinc- 
tively to some snug corner or well-curtained recess. The 
temperature of this restricted space is higher than that of the 
open world, so that the relapse of the winter-sleeper into a sort of 
reptilian cold-bloodedness is not fatal. If they hibernated in the 
open it would be the end of them, but in a recess they do well. 


Condensation into Small Bulk 


In plants like tulips and hyacinths, we see another way of 
meeting the winter—the whole body of the plant is condensed 
into more compact and less vulnerable form. In the same way 
the shedding of leaves is like a relinquishing of outposts when 
hard pressed. A bud is a shoot in winter-quarters. A very 
interesting case is that of the rootless Bladderwort of the loch, 
that captures water-fleas in tiny traps on its floating stem. In 
autumn the terminal buds, heavily laden with reserves, drop 
off and sink to the warmer water at the bottom; whence, light- 
ened, they float up again in spring and start new plants. This 
is to be compared to the not very familiar well-protected external 
buds (“hibernacula’’) of colonies of small aquatic animals called 
Polyzoa, which persist throughout the winter when the rest of 
the colony dies. Similarly, the freshwater sponge in the river 
or lake rots away in the autumn, but does not wholly die. 


1072 The Outline of Science 


Certain clusters of cells called gemmules appear in the moribund 
body, each well compacted together, and encased in beautiful 
capstan-like spicules of flint which fit closely into one another. 
These start new sponges in the spring. Although they are not 
very well known, there are many illustrations of this method of 
meeting the winter by condensation and encystation. 

Another solution, already referred to in connection with 
autumn, is laying up stores. The squirrel with its stores of nuts 
is the instinctive counterpart of the intelligent housewife; the 
hamster with its stores of grass and grain is the instinctive 
counterpart of the intelligent farmer. It must be recognised 
that the storing habit in hive-bees is an essential condition of 
the persistence of the community throughout the winter. It is 
interesting to know of the Mediterranean ant, A phenogaster 
sardoa, which lives in holes in the ground, but does not store. 


Huddling together is their form of sociality. They form 
living balls, ant interlocked with ant by the mandibles and 
tarsal joints, and they hold the eggs, larve, and pupz in the 
middle. It is almost like a diagram of a primitive society 
and certainly matriarchal! A ball consists of three hundred 
to a thousand individuals; males have not been found; and 
the investigator saw only one queen. In winter the ball is 
very stiff and is slow to relax when it is unearthed. In 
summer, however, the ball is naturally more plastic, it is 
always being unmade and remade.' 


Now the point is, that this simple case, where the whole communal 
life is summed up in huddling together, is the beginning of the 
ant-hill, in which abundant storing has made more elaborate 
social life possible. 


Migration 


Neatest of all the solutions is the circumventing of the 
winter, illustrated by the migratory birds, which literally “know 


no winter in their year.” Enough has been said of this in the 
*Thomson, The Wonder of Life, 1914, p. 331. 


The Biology of the Seasons 1073 


article on Birps, but a reference is necessary here to complete 
our survey. It has become engrained in the constitution of the 
great majority of our North Temperate birds to pass in autumn 
from their nesting-place—always in the colder part of their 
migratory range—to a resting-place in warmer southern lands. 
The neatest way of meeting the winter is to evade it altogether, 
and that this is relative is plain enough from the fact that many 
a curlew finds it sufficient to descend from the inhospitable moor- 
land to the fields by the shore, and that many a lapwing finds it 
enough to pass from Aberdeenshire to Ireland. It must also be 
noted that various birds that nest in the farther North, such as 
fieldfare, redwing, snow bunting, great northern diver, and little 
auk, find Britain very congenial in winter, and are our “winter 


visitors.’ . 


Reduction of Numbers 


On a different tack altogether is the solution of the winter 
problem which is suggested by the empty wasps’ nest. ‘There has 
been a drastic reduction of the population, so that only the young 
queens are left to survive the winter, which they pass in solitude 
and lethargy in the shelter of some partly broken tree stem. 
Towards the end of the autumn there is a grim tragedy in the 
wasps nest, for the wasp-grubs that are left in their cells are 
devoured. But this wholesale infanticide is only anticipating the 
death which the cold weather would soon bring about, and it 
may be that the gorging helps the young queens to pass the 
winter months in their cupboardless hiding-places. The same 
kind of solution is exhibited elsewhere, as in the case of the 
humble-bees, for of the large summer community only the young 
queens live on through the winter. 


Elimination 


Such cases naturally lead us to the conspicuous fact in the 
Biology of Winter that it is a time of sifting—the time of 


VOL. IV—14 


1074 The Outline of Science 


severest elimination. Winter is indeed an opportunity for rest 
and recuperation, but it is also an opportunity for winnowing. 
The rest and sleep of winter are often the necessary conditions of 
the vigour of another spring, but in a deeper way it is through the 
sifting, winnowing, pruning, or elimination of ages of winters 
that there has been spring after spring of progressive evolution. 


BIBLIOGRAPHY 


ALLEN, Grant, Colin Clout’s Calendar (1883). 

Breese, The Log of the Sun (1906). 

Burrovaus, Joun, Signs and Seasons (1886). 

CassELL’s admirable Nature-Book (1908). 

Hammerton, The Sylvan Year (1896). 

Miau, Round the Year (1896). 

RENNIE, Aims and Methods of Nature Study (1910). 

Tuomas, Epwarp, and others, British Country Life (2 vols.). 

Tuomson, The Biology of the Seasons (1911); The Wonder of Life (1914) and 
Nature all the Year Round (1920). 

Wuite, GiiBert, The Natural History of Selborne (1788). 

WircHe 1, Nature’s Story of the Year (1904). 

Woop, J. G. anp Tu., The Field Naturalist’s Handbook (1879). 


XXXIV 
WHAT SCIENCE MEANS FOR MAN 


By Sir Ontver LopGE 


1075 


WHAT SCIENCE MEANS FOR MAN 


LIFE, MIND, AND MATTER 
By Sir Oxutver Lopcr 


HERE are three things partly within and partly beyond 
human reach—Truth, Goodness, and Beauty. All are 
necessary for completeness, and a Being in whom they all 

reach perfection would be what we call Divine. But with our 
limited capacities few of us can do more than aim at one of them; 
though, if we are able to retain the open mind, we may hope that 
by faithful effort in one direction something of the two others 
may be “added unto us.” 


The Aim of Science 


The direct aim of Science is Truth, and the temptation of 
its devotees is to concentrate too narrowly on this one aim and 
lose sight of the wealth of existence which gives all the meaning 
and value to bare fact; thus gaining but a purblind view of the 
universe, in spite of a large accumulation of knowledge which is 
accurate as far as it goes, but so incomplete as regards the totality 
of things as to be liable to mislead. 

But such narrow students of science are not Philosophers. 
They may pose as such occasionally, and be loud in the negation of 
everything outside their own range, but true philosophy must take 
a wider view, it must open its eyes in every direction, and seek to 
comprehend the length and breadth and depth and height, and to 
interpret something of the great Reality which passeth knowledge. 


Only so can the man of science escape the narrowness of 
1077 


1078 The Outline of Science 


specialisation; he must keep his mind open to the Universe in 
every direction, if he is to perceive something of the fullness of ex- 
istence. But to Truth he must be faithful. That is his peculiar 
quest, and no slackness in making sure of his facts can be permit- 
ted to the scientific man. Narrowness of range is a pity, but it 
is pardonable; blasphemy against the spirit of Truth can never 
be forgiven. 

The particular aspect of the Universe which most impresses 
the man of science, at any one epoch, is liable to vary. E:xistence 
is so multifarious and bewildering in its scope and variety that not 
only has humanity to make distinctions and contemplate things 
seriatim, but investigators must divide themselves into groups, 
and each group attend specially to its own department. 

In this way Science has become split up into a number of 
sections, and the workers in one section are often ignorant 
of what the others are doing. A wide philosophy under 
these circumstances is impossible. It is only by getting out 
of our groove, from time to time, and attempting a survey, that 
we can assist the philosophers, who perhaps have never entered a 
groove at all. ‘They seem to us to be too thinly supplied with 
facts, whereas we are apt to be overburdened with a lop-sided 
load of them. Hence Philosophers and Scientific men often fail 
to understand each other and sometimes quarrel. 


1 
Outlook on the World : 

Looking round, then, on existence, with eyes clouded a little 
by special study but as widely open as we can get them, what do 
we see? 

An unbounded universe of space, containing spherical masses 
of matter, some hot and glowing, some dark and cool, distributed, 
not at random, but obedient to law and order, with motions that 
can be formulated and positions that can be more or less pre- 
dicted. Examining Matter more closely, with the help of instru- 


What Science Means for Man 1079 


ments of precision, we find it consists of atoms of known size and 
behaviour, and we find also that these ultimate atoms of matter 
are not really ultimate but are composed of something else, 
something that we call electricity. And this electricity also exists 
in little specks, which appear to imitate the larger masses in their 
regular motions, and which display a region of beautiful law and 
order in the very interior of the atom. Then when we come to 
investigate the intermediate region of apparently empty space we 
find that it is not empty, but contains a something that welds all 
the separate fragments of matter into a cosmic whole, and also 
that it carries vibrations and transmits force from one to another. 
And all this study of matter and ether, with its extraordinary 
ramifications, belongs to the science of Physics, or, as it used to 
be called, Natural Philosophy. 

The laws of motion of the particles and masses of matter are 
so elaborate that they require for their elucidation and study an 
abstract science of form and number which we call Mathematics. 
With its aid a vast theoretical structure can be built upon a com- 
paratively small basis of actual experience. The process is a 
wonderful example of brain-power, but it is risky; mistakes and 
oversights may readily be made; and accordingly every deduction 
must be brought to the test of experiment, and observation, and 
rigorously verified. ‘The two fundamental branches of mathe- 
matics relate to Number and Form; that is to say, Arithmetic 
and Geometry. Algebra is an auxiliary art or method of dealing 
with problems which otherwise would be too difficult. 

Further, we can study the grouping of the atoms together, 
the patterns they make when they combine into molecules, and 
the complicated properties characteristic of the substances which 
their groupings form. So men have built up that great branch of 
Natural Philosophy which is known as the science of Chemistry. 

Certain collocations of these complicated molecules give ex- 
pression to a new emergence of Reality, for they are able to form 
the physical basis of living creatures or organisms. These are the 


1080 The Outline of Science 


seat of chemical and physical processes, but we cannot deal 
adequately with living creatures, e.g. in their behaviour and 
development, by means of chemical and physical formule and 
concepts alone. 

It appears that they are controlled and utilised by something 
that we call Life; or else, as some desire or prefer to express it, 
the complexity of their molecular structure enables them to simu- 
late such a control. Thus arises the science of Biology. Under 
the influence of life the available energy of the world, which 
all arrives from the sun, is guided and directed so as to produce 
structures such as would never be produced by unaided Physics 
and Chemistry (for instance, sea shells, honeycombs, leaves, 
and birds’ nests), though all that goes on is wholly obedient to 
the laws of ether and matter. But those laws are supplemented 
by the activity of something that we call life; and the result is 
a world of plants and animals, flowers and birds, an extraordinary 
world of beauty and animation and instinct, and something surely 
akin to joy. 


Evolution of Mind 


A further development makes this manifest, for life gradu- 
ally evolves into mind; and through Mind we know at first hand, 
and from our own experience, that joy and sorrow, pain and 
grief, love and hate, aye, and thought and design, will and desire, 
feeling and aspiration, hope and faith, are realities certainly 
existent in the totality of things, however they can be accounted 
for. So comes into being the science of Psychology, and other 
developments, up to those gropings of the spirit of man that 
we call, on their practical side, Religion, and in their theoretical 
aspect, Theology. 

These may be regarded as the major sciences, but there are 
many minor ones having to do with special portions of the 
Universe: like Geology and Geography and Meteorology, all 
related to the earth; others to do with man, like History and 


MICHAEL ANGELO IN HIS STUDIO 


** We still feel the force of Michael Angelo, wearing the four crowns of architecture, sculpture, painting, and poetry.”— EMERSON. 


JOHN KEATS 


Beauty is truth, truth beauty—that is all 
Ye know on earth, and all ye need to know. 


—KEaTs. 


BEETHOVEN 


The master, perhaps the greatest of all masters, of music. 
Beethoven said, ‘‘ Music is the mediator between the spiritual 
and the sensual life.” 


What Science Means for Man 1081 


Sociology and Anthropology and Archxology. And, of course, 
Biology has many branches, such as Physiology—the mode of 
working of the animal or vegetable organism and Anatomy, its 
structure; also Zoology and Botany, dealing with the classifica- 
tion and habits of living things. Then, again, others have to 
do with practical applications, like Engineering and Medicine 
and Agriculture. The abstract science of number and form called 
Mathematics we have already referred to; and the separate branch 
of physics called Astronomy must be mentioned. 


§ 2 


Does, then, Science cover the whole of existence? By no 
means. There is the region of Art and Literature, and the whole 
realm of the good and the beautiful, which lie outside its scope. 
As human beings we have the right of entry; as men of science we 
must ask permission to enter. If we ignore all this realm, we 
suffer, and our philosophy is little better than dry bones—a 
skeleton which others may clothe with flesh and wake to life. 
(Readers who desire a more eloquent exposition of the relation 
between science and the rest of existence should read the Intro- 
duction to Science in the Home University Library, by Prof. 
J. Arthur Thomson. ) 

- The human spirit is more at home in Poetry and Literature 
and Art than it is in the gropings and cautious investigations 
of Science. It is able to leap to conclusions by intuition. It 
likes to disport itself with full and untrammelled imagination. 
It is privileged to enjoy, and so far as may be to produce, beauty, 
in music, in painting, in architecture, in poetry. And its achieve- 
ments in these directions—Sonatas, Parthenons, and Divine 
Comedies—are of supreme interest to humanity, and rank among 
the highest creations of man. For in this region it is not discovery 
that is arrived at, but veritable creation—the production of some 
work of art that would not otherwise come into existence, and 
before which the man of science can only bow his head. Men 


1082 The Outline of Science 


like Shakespeare, Dante, Michael Angelo, Beethoven, love and 
perceive the principles of Goodness, Truth, and Beauty, all 
three; and have thus caught some glimpse of the Unchangeable 
Reality. 

There is no antagonism between poetry and science. There 
should be no antagonism between religion and science. ‘There are 
many ways of arriving at Truth, the scientific path is but one. 


Beauty and Truth 


We have said that the conscientious pursuit of Truth may 
perhaps lead us to some apprehension of Goodness and Beauty, 
too. So it may be that the reverent pursuit of Beauty will lead 
us intuitively into the realm of Truth—as Keats more concisely 
said. And what the earnest following of the Good may do for 
man has been shown by the achievements and inspiration of the 
saints; the full meaning of which we are as yet hardly competent 
to judge. The mind of man is enriched from many diverse 
channels; the feet of man are guided up the ascent by many 
diverse paths. ‘The aims are different, the goal may be one. 
All roads lead to Rome, and all avenues conscientiously explored 
lead in the direction of the Truth. For the Truth is larger than 
what any man deems possible, and no one man or group of men 
has any monopoly over that divine fragrance. Hidden and rare 
and yet dazzling and splendid, she emerges from her enwrappings, 
more beautiful than ever we had imagined and grander than any- 
thing we had conceived. 


§ 3 
RELATION BETWEEN LIFE, MIND, AND MATTER 


Life, Mind, and Will 

These things being so, how can we acquiesce in the material- 
ism of science, or justify the scientific man in excluding from his 
attention so many aspects of the universe and attending to the 
laws of forces and the motion of matter? The answer is, because 


What Science Means for Man 1083 


that is his proper business, and because the whole of nature is 
obedient to these fundamental laws, no matter what other laws 
it may be also obedient to. Exclusion from attention is perfectly 
legitimate if it assists the business in hand, and has no sort of 
connection with a materialistic philosophy which affirms some 
things and denies others. Thus Laplace, when catechised by Na- 
poleon as to the place of God in his mathematical System of the 
World, was right in replying that he did not need that hypothesis, 
because he was working out his theory in accordance with the laws 
of matter and force alone. And a splendid achievement it was! 
Not complete as a philosophy of existence—certainly not. Nor 
was Newton’s still greater, because earlier and more fundamental, 
theory complete philosophically; and, indeed, he felt this so 
strongly that he diverges and ends his book with a reasoned 
assertion of his profound faith in a Divine Being. Nevertheless, 
he had reduced the heavens to law and order on purely mathe- 
matical lines; and he went further and uttered the pregnant 
aspiration, which since his time has been so extensively fulfilled, 
that all the rest of physics—everything depending on the motion 
of the atoms and of the electrons, and upon all the intricacies of 
molecular constitution and movement—might be similarly dealt 
with: “WouLpD THAT THE REST OF THE PHENOMENA OF NATURE 
COULD BE DEDUCED BY A LIKE KIND OF REASONING FROM MECHAN- 
ICAL PRINCIPLES!” Yet he was a Theist of the most profound con- 
viction. Whether Laplace was, or was not, I do not know; but 
it does not matter: his achievement was not in philosophy or 
theology, but in mathematical science. And he made the famous 
supposition that, given certain data and sufficiently superhuman 
mathematical skill—so that the path of every atom could be 
followed, its past orbit ascertained, and its future orbit predicted 
—all the phenomena of nature past and future could be calcu- 
lated out and would inevitably follow. 

So they would if the universe were solely mechanical, and if 
there were not the element of life, mind, and will, in addition. 


1084 The Outline of Science 


The introduction of self-will or free-will shatters the completeness 
of every purely mechanical scheme. Predictions can only hold 
good in the absence of a disturbing cause; and the predictions of 
Laplace’s Calculator would be valid only in the region of inani- 
mate matter, and perhaps in the regions animated by the lower 
forms of life. 

How early spontaneous activity occurs, in the ascending 
grade of existence, is a matter for discussion; but in my view the 
path of a common fly, as it sports’ with others round a pendant 
from the ceiling, is not likely to be deducible from any physical 
data on purely mechanical principles. And, if that is so, it means 
that an incalculable element introduces itself very low down in the 
scale of animal life, even though physical or mechanical principles 
alone dominate the vegetable kingdom; which some may doubt. 

Life does not break any of the laws of chemistry and physics. 
It employs them all. Butit supplements them. It directs energy 
into new channels. It cuts through an isthmus and unites two 
oceans. It builds a viaduct and unites two countries. It plants 
a forest, or floods a desert, and alters a climate. It can divert 
rivers, and tunnel through mountains; it has developed the mani- 
fold structure of civilisation. And, lower down in the scale, it 
collects wax and builds a honeycomb; it consumes corn and 
produces a feather—a marvellous structure when closely ex- 
amined; it lives on a cabbage leaf and develops the beauty of a 
butterfly’s wing. 

So also, and par ewcellence, the spirit of man rises superior 
to bodily and material trammels, and disports itself in the region 
of intellect and imagination and poesy. ‘Things beyond experi- 
ence become food for its contemplation, and it feels itself akin to 
the infinite and the eternal. 


§ 4 


Nature of Life 


What, then, do we know about this organising principle 
that we call “life”? Exceedingly little. 


JOHN RUSKIN 


“We cannot fathom the mystery of a single flower. Noris 
it intended that we should, but that the pursuit of science 
should constantly be stayed by the love of beauty, and accu- 
racy of knowledge by tenderness of emotion.’’—Modern 
Painters. 


GOETHE 


He pursued a lonely road, 
His eyes on Nature's plan; 
Neither made man too much a God, 
Nor God too much a man. 
—MAatTTHEW ARNOLD. 


Photos: Rischgitz Collection. 
J. Mo Wa TURNER, R.A. 


“Tt is as the master of the science of Aspects, that... 
Turner must eventually be named always with Bacon, the 
master of the science of Essence.’’—RUSKIN. 


DANTE 


“The first awakener of entranced Europe .. . the con- 
gregator of those great spirits who presided over the resurrec- 
tion of learning.’’—SHELLEY. 


What Science Means for Man 1085 


The living organism was shown by Pasteur to be responsible 
for a good many processes which up to this time had been re- 
garded as merely chemical. Chemical they still are, but guided in 
fashion; much as similar chemical changes may be guided and con- 
trived by the skill of a chemist in his laboratory. Unconsciously, 
through the agency of microscopic forms of life, fermentation 
and digestive operations are carried on, agriculture is aided or 
rendered possible, and diseases are both produced and combated. 

One must not dogmatise on what has been and probably is a 
controversial subject, but the possibility that “life” may be a real 
and basal form of existence, and therefore persistent, is a likeli- 
hood to be borne in mind. The idea may at least serve as a clue 
to investigation, and some day may bear fruit; at present it is 
no better than a working hypothesis. It is one that on the whole 
commends itself to me; for I conceive that though we only know 
of life as a function of terrestrial matter, yet it presumably has 
another aspect, too. And I say this because I see it arriving and 
leaving—animating matter for a time and then quitting it—just ’ 
as I see dew appearing and disappearing on a plate. Apart from 
a solid surface, dew cannot exist, as such; and to a savage it might 
seem to spring into and to go out of existence—to be an exudation 
from the solid, and dependent wholly upon it. But we happen to 
know more about dew than that; we know that it has a permanent 
and continuous existence, in an imperceptible, intangible, super- 
sensual form, though its visible manifestation in the form of mist 
or dew is temporary and evanescent. Perhaps it is permissible to 
trace in that elementary phenomenon some superficial analogy 
to an incarnation. 

So, also, when we come to the higher manifestation of life 
that we call mind and will. These things are not energy, but they 
utilise energy, and direct it into prearranged channels. ‘They aim 
and fire, as it were. ‘They discriminate between friend and foe, 
they attend to things far beyond the scope of material force; they 
have ulterior motives, and are influenced by anticipation of the 


1086 The Outline of Science 


future. The blind energy of an explosive is liberated, and neither 
increased nor diminished; but its manner of application, and 
therefore the result attained, can be a subject of consideration 


and can be preordained. 


The Essence of Mind 

Matter possesses energy, in the form of persistent motion, 
and it is propelled by force; but neither matter nor energy is 
endowed with the power of automatic guidance and control. 
Energy has no directing factor, it has no element or ingredient 
of direction, it possesses magnitude only. In that respect energy 
is like matter. It is also conserved like matter; and it is amenable 
to directing influences, which are applied to it indirectly through 
the agency of material force. 

To change the course of a fragment of matter, a force must 
act upon it. Matter itself has no spontaneity, it is entirely inert. 
Inorganic matter is impelled solely by pressure from behind; 
to everything in front it is perfectly blind; it is not influenced 
by the future; nor does it follow a preconceived course, nor seek 
a predetermined end. 

An organism animated by mind is in a totally different case. 
The intangible influences of hunger, of a call, of perception of 
something ahead, are then the dominant feature. An intelligent 
animal which is being pushed is in an ignominious position and 
resents it; when led, or when voluntarily obeying a call, it is in its 
rightful attitude. 

The essence of mind is design and purpose. There are some 
who deny that there is any design or purpose in the universe at 
all. But that cannot possibly be maintained when humanity itself 
possesses these attributes. Is it not more reasonable to say that 
just as we are conscious of the power of guidance, in ourselves, 
so guidance and intelligent control must be an element running 
through the universe, and may be incorporated even in material 
things? 


What Science Means for Man 1087 


Matter the Vehicle of Mind 


Matter is the instrument and vehicle of mind; incarnation is 
the mode by which mind interacts with the present familiar scheme 
of things; and thereby the element of guidance is supplied. It 
can, in fact, be embodied in an intelligent arrangement of inert 
inorganic matter. Kven a mountain path is a concrete expression 
of something human; it is able to guide, and it has direction; it 
is a manifestation of intelligence, it leads to a destination, though 
_ itself inert. 

Direction is not a function of energy. The energy of sound 
from an organ is supplied by the bellows, which may be worked 
by a mechanical engine; but the melody and harmony, the 
sequence and coexistence of notes, are determined by the domi- 
nating mind of the musician; not necessarily by that of the execu- 
tant, for the composer’s mind may be expressed to some extent 
even by a pianola. The music may be said to be incarnate in the 
roll of paper which is ready to be passed through the instrument. 
So also can the conception of any artist receive material embodi- 
ment in his work, and if the picture or a beautiful building is 
destroyed it can be made to rise again from the ashes, provided 
the painter or the architect still lives. In other words, his 
thought can receive a fresh embodiment; and a perception of 
beautiful form shall hereafter, in a kindred spirit, arouse similar 
ideas. 

There is thus a truth in materialism, but it is not a truth 
readily to be apprehended and formulated. Matter may become 
imbued with life, and full of vital association; something of the 
personality of a departed owner seems to cling sometimes about 
an old garment—its curves and folds can suggest him vividly 
to our recollection. The tattered colours of a regiment are some- 
times thought worthy to be hung in a church. They are a symbol 
truly, but they may be something more. I have reason to believe 
that a trace of individuality can cling about terrestrial objects in 
a vague and almost imperceptible fashion, yet to a degree suf- 


1088 The Outline of Science 


ficient to enable those traces to be detected by persons with suita- 
ble faculties. 

There is a deep truth in materialism; and it is the foundation 
of the material parts of worship—sacraments and the like. It is 
possible to exaggerate their efficacy, but it is also possible to 
ignore it too completely. ‘The whole universe is metrical, every- 
thing is a question of degree. A property like radio-activity or 
magnetism, discovered conspicuously in one form of matter, 
turns out to be possessed by matter of many kinds, though to 
very varying extent. 

So it would appear to be with the power possessed by matter 
to incarnate and display mind. 


Grades of Incarnation 

There are grades of incarnation: the most thorough kind is 
that illustrated by our bodies; in them we are incarnate, but 
probably not even in that case is the incarnation complete. It is 
quite credible that our whole and entire personality is never 
terrestrially manifest. This, indeed, is part of the doctrine of 
“the subliminal self.” 

There are grades of incarnation. Some of the personality of 
an Old Master is locked up in a painting; and whoever wilfully 
destroys a great picture is guilty of something akin to murder, 
namely, the premature and violent separation of soul and body. 
Some of the soul of a musician can be occluded in a piece of 
manuscript, to be deciphered thereafter by a perceptive mind. 

Matter is the vehicle of mind, but it is dominated and trans- 
cended by it. A painting is held together by the cohesive forces 
among the molecules of its pigments, and if those forces rebelled 
or turned repulsive the picture would be disintegrated and de- 
stroyed; yet those forces did not make the picture. A cathedral 
is held together by inorganic forces, and it was built in obedience 
to them, but they do not explain it. It may owe its existence and 
design to the thought of someone who never touched a stone, or 


What Science Means for Man 1089" 


even of someone who was dead before it was begun. In its 
symbolism it represents One who was executed many centuries 
ago. Death and Time are far from dominant. 

Are we so sure that when we truly attribute a sunset, or the 
moonlight rippling on a lake, to the chemical and physical action 
of material forces—to the vibrations of matter and ether as we 
know them—we have exhausted the whole truth of things?) Many 
a thinker, brooding over the phenomena of Nature, has felt that 
they represent the thoughts of a dominating unknown Mind 
partially incarnate in it all. 


VOL. IV—I5 


XX XV 


im 5 
ae 


ETHNOLOGY _ 


» if 
ae 


ETHNOLOGY 


HERE are sound reasons for regarding the existing races 
of mankind as varieties of one species, Homo sapiens, just 
as the numerous breeds of pigeons are offshoots from the 

ancestral stock of the rock-dove. One reason is that, so far as is 
known, the members of the different races are fertile with one 
another, giving rise to fertile crosses, such as mulattos. Another 
reason is that the embarrassingly numerous races grade into one 
another. And a third reason may be found in the extreme im- 
probability that such a happy new departure as “the modern man 
type’ (Homo sapiens) would arise more than once in evolution. 
It is likely that some tentative types, like Neanderthal Man, 
antecedent to “the modern man type,” became extinct or were 
absorbed; it is likely that Homo sapiens arose from a stock which 
he shared with the Neanderthal, the Heidelberg, and the Pithe- 
canthropus races. 


One Species with Many Races 


The number of different races of man is very large, but the 
phenomenon is familiar at lower levels. A group of living 
creatures belonging to a species becomes in some way isolated; 
variations or mutations may occur in the families, and they are 
often numerous; selection or sifting sets in and the variants which 
are fittest in relation to the particular conditions of life become 
dominant over their neighbours; inbreeding occurs, and the new 
characters become firmly established, while analogous recessive 


characters with a disadvantageous bias are sifted out; a race is 
1093 


1094 The Outline of Science 


established. 'Thus, if the original colour of man was brown, a 
dark-coloured race or a white race may have arisen over and over 
again in different parts of the earth. It must be understood also 
that a removal of isolation barriers, e.g. by a migration or an 
invasion, would tend to bring about a mingling of races, and as a 
result, new permutations and combinations. Inbreeding promotes 
stability and uniformity ; outbreeding promotes variability, unless 
the divergence of the parents is too pronounced. One is apt 
to underestimate the possibilities of novelties. Prof. E.G. Conk- 
lin writes: 


The principles of Mendelian inheritance show that for every 
pair of contrasting characters in the two parents, as for 
example straight or curly hair, brown or blue eyes, there are 
two types of grandchildren showing these characters; when 
there are five such pairs of contrasting characters in the 
parents, there may be (2)° or 32 types of grandchildren 
showing various combinations of these five characters; when 
there are ten pairs of contrasting characters, there may be 
(2)*° or 1,024 types of grandchildren. Between different 
races there are many more than ten unit differences, and thus 
with a relatively small number of mutant characters an 
enormous number of different combinations of the characters 
is possible in the offspring. Subsequent inbreeding of such 
a mixed race leads to the separation or segregation of par- 
ticular types, having certain of these combinations, from 
other types having other combinations. 


As with domestic animals and cultivated plants, so with human 
races; mutations or variations arise (as to the conditions determin- 
ing the origin of the distinctly new, there is little certainty) ; there 
is sifting by selection and stabilising by inbreeding; there is 
mingling with fresh blood and a fresh shuffling of the hereditary 
cards; there emerges a new set of novelties; there is sifting and 


inbreeding again. In outline, that is how race-forming has come 
about. 


THE RED “INDIAN’’ 


The American ‘‘Indians” in former times occupied a vast extent of territory. Yet they present a remarkable uniformity in regard 


to their physical characters, though linguistically and in culture they differ widely. 
‘‘Story-books” and the early Colonists from England have familiarized the world with the North American Indian, or ‘‘ Red-skin,”’ 


but his relatives of South America are no less interesting, although in many ways less picturesque. 


Ethnology 1095 


$1 


The Primary Groups of Mankind 


More for convenience than with conviction, ethnologists are 
accustomed to recognise three primary groups of human races— 
the black, the yellow, and the white. Each group has numerous 
subdivisions or races, each race may have its sub-race, each sub- 
race its breeds, each breed its stocks. 

1. The group of Black or Negroid races is typically char- 
acterised by darkly pigmented skin, frizzly hair, a broad flat nose, 
thick lips, prominent eyes, large teeth, a narrow hip-girdle, and 
long heads (dolichocephaly). But there is great variety within 
the group, which includes African negroes, South African bush- 
men, various Pygmy races, together with such divergent types 
as the Melanesians and the Australian blackfellows (who have 
not frizzly hair). 

2. The group of Yellow or Mongolian races is typically 
characterised by yellowish skin, black straight hair, broad face 
with prominent cheek-bones, small nose, sunken narrow eyes, 
moderately sized teeth, and diverse types of skull. Here come in 
Chinese, Japanese, Tibetans, Siamese, Burmese; Malays, Brown 
Polynesians, Maoris, Esquimaux, and Red Indians; and most 
divergent of all, the Lapps and Finns, the Magyars and Turks. 

3. 'The group of White or Caucasian races is typically char- 
acterised by soft and straight hair, well-developed beard, retreat- 
ing cheek bones, narrow and prominent nose, small teeth, and 
broad hip-girdle. But the group includes along with the fair- 
haired and white-skinned peoples of northern Europe, the dark- 
haired and often dark-complexioned southerners. Thus in 
Europe we may distinguish the tall and blond Nordics, the 
stocky dark Alpines, and the small dark Mediterraneans, 
while in Asia there are the Indo-Aryan and other types. It 
hardly requires to be said, for the heterogeneity of our enumera- 
tion is so evident, that these three primary groups—Negroid, 


1096 The Outline of Science 


Mongolian, and Caucasian—do not mean very much scientific- 
ally; yet everyone will admit that a Persian is nearer to a Britisher 
than a Hottentot is, and we think we understand what an Arab 
is after, while a Chinaman remains a sphinx. 


A Change of Outlook 

A generation ago it was thought possible to distinguish 
three “primary races’—a phrase we have not used—black, 
yellow, and white; and it was commonly thought that these 
represented a very ancient trifurcation of the human species. 
But there are good reasons for suspecting that this view—which 
we might call “the Shem, Ham, and Japheth” view—is all too 
simple. No doubt the contrasts are striking and real. 


We are all familiar [Sir Arthur Keith writes] 
with the features of that racial human type which clusters 
round the heart of Africa; we recognise the negro at a glance 
by his black, shining, hairless skin, his crisp hair, his flattened 
nose, his widely opened dark eyes, his heavily moulded lips, 
his gleaming teeth and strong jaws. He has a carriage and 
proportion of body of his own; he has his peculiar quality of 
voice and action of brain. He is, even to the unpractised 
eye, clearly different from the Mongolian native of north- 
eastern Asia; the skin, the hair, the eyes, the quality of 
brain and voice, the carriage of the body and proportion of 
limb to body serve to pick out the Mongol as a sharply dif- 
ferentiated human type. Different from either of them is 
the native of central Kurope—the Aryan or Caucasian type 
of man; we know him by the paleness of his skin and by 
his facial features—particularly his narrow, prominent nose 
and thin lips. We are so accustomed to the prominence of 
the Caucasian nose that only a Mongol or Negro can ap- 
preciate its singularity in our Aryanised world. 


Now if the distinctive features are so well-marked as this great 
authority indicates, why should we hesitate to accept them as in- 


Ethnology 1097 


dicative of a fundamental trifureation of the human species? 
The answer is interesting. 


§ 2 

Hormones and Ethnology 

At many points in this OUTLINE OF SCIENCE reference has 
been made to the ductless glands of internal secretion which 
manufacture “hormones” and “chalones’’—potent chemical mes- 
sengers discharged into the blood. The pituitary body, “about 
the size of a ripe cherry, attached to the base of the brain, and 
cradled in the floor of the skull,” makes a secretion that regulates 
growth. An abnormal enlargement brings about “acromegaly,” 
which profoundly alters the character of face and body, hands 
and feet; or the youth may become an unhealthy giant; or the 
limbs may grow disproportionately long, and the sex system 
fail to develop properly—the result being sometimes eunuchoid 
obesity. 


We are justified [Sir Arthur Keith says] in regarding the 
pituitary gland as one of the principal pinions in the 
machinery which regulates the growth of the human body 
and is directly concerned in determining stature, cast of 
features, texture of skin, and character of hair—all of them 
marks of race. When we compare the chief racial types of 
humanity—Negro, the Mongol, and the Caucasian or Euro- 
pean—we can recognise in the last-named a greater pre- 
dominance of the pituitary than in the other two. The 
sharp and pronounced nasalization of the face, the tendency 
to strong eyebrow ridges, the prominent chin, the tendency 
to bulk of body and height of stature in the majority of 
Europeans are best explained, so far as the present state of 
our knowledge goes, in terms of pituitary fufiction. 


Before this view can be accepted in its entirety, there must be 
very precise comparisons of the pituitary body in different races, 
for Science begins with measurement. But the idea is plainly 


1098 The Outline of Science 


a shrewd one. It does not mean that the European is an acro- 
megalic in disguise; it means that variations in the development 
of the ductless glands may account for some of the changes that 
are rung on human characters. There is some evidence that 
some of the extinct giant Vertebrates had relatively large pitui- 
tary bodies. Variations in the development and activity of these 
regulating organs may have played an important part, not only 
in the evolution of human races, but in the evolution of Verte- 
brate types. 

We must not follow this fascinating line of thought much 
further, but it may be noted that the hormones from the repro- 
ductive organs have a profound influence on many characters of 
the body; that the supra-renal secretions affect pigmentation and 
hair; that the thyroid glands, set astride the windpipe just be- 
hind ““Adam’s apple,” influence skin and hair, skull and skeleton; 
that two kinds of dwarfs are due to a defect in their growth regu- 
lating function; that the abnormal children, significantly called 


3 


“Mongolian idiots,” are not reversions to hypothetical Mongo- 
lians supposed to have once lived in Europe, but are the outcome 
of disordered thyroid functioning. Given a susceptible struc- 
ture, variations in the internal secretions may account for many 
features which have been over-exalted as deep racial differences. 
On the other hand, we must not minimise these racial differences 
because Sir Arthur Keith gives us a clue which makes them 
more intelligible. The difference between male and female is a 
very profound one, and none the less far reaching because it may 
turn out to be fundamentally a difference in the rate and rhythm 
of metabolism, or because the actualisation of some of the 
secondary sex characters depends on the liberating stimulus 
supplied at appropriate times by hormones from the reproductive 
organs. 

It is a luminous idea, however, that racial differences in 
skull and skin, in hair and colour, may be correlated with 


hereditary variations in the ductless glands; and we see the likeli- 


Photo: E. N. A. 


A MAORI 


The Maoris are commonly regarded as a practically pure 
Polynesian race. But this is by no means true. In their 
passage to New Zealand they interbred with several other 
distinct races, traces of which are indubitably present in the 


skull. 


Photo: Bourne & Shepherd, India. 
HINDU 


The Hindu represents but one of a number of very distinct 
races in India, and is properly restricted to the Indo-Gangetic 
region of India. 


Photo: H. J. Shepstone. 


Son 
ee 
, ot 
13 
3 
3 
E 
i 
‘ 


ZULU 


An irregular line drawn across Africa from the southern 
end of Italian Somaliland in the east to Calabar in the west 
divides the true negroes from the Bantu, which occupy the 
area south of this line. The Bantu are represented by in- 
numerable tribes and races, of whom the Zulus are the most 
warlike and the most powerful. 


Photo: H. J. Shepstone. 


ARAB 


The Arabs occupy Arabia, part of Mesopotamia, the shores 
of the Red Sea, the eastern coast of the Persian Gulf, and the 
North of Africa. The pure type is long-headed, has an elon- 
gated face, an aquiline nose, and a slim figure. The most 
typical specimens of this race are found in South Arabia, the 
mountaineers of Hadramaut and Yemen, and among the 
Bedouins. 


Photo: H. J. Shepstone. 
JEW 


JENN OS IB... IN, ANS 
A CANTONESE GENTLEMAN 


The Chinese people have sprung from many intermixtures. 
Today there is a marked difference between the Northern 
and the Southern Chinese. Those of Central China have 
retained more of the original characters of the race. The 
Southern Chinese belong, very largely, to the Southern Mon- 
golian race, and are short, round-headed people. 


Physically the Jews present two different types—and blends 
thereof. One approximates to the Arab race, as in this 
photograph, the other to the Assyriod, in which the nose has 
the characteristic shape commonly designated ‘“‘ Jewish.” 


Photo: E. N. 


A TYPICAL ESKIMO 


Ethnology 1099 


hood that the same types, e.g. Pygmies, may have arisen re- 
peatedly on different lines of evolution, and in widely separated 
parts of the world. Modern science has transformed the old 
“Ham, Shem, and Japheth” doctrine. 


§ 3 
The Making of Races 

Ethnology studies races rather than nationalities; and by a 
race is meant a sub-species or a variety—a group of individuals 
with many features in common, and with a community of 
ancestry within itself greater than that between it and another 
race. But the difficulty is to find pure races in modern times— 
after so many centuries of intermingling. A race may consist 
of clans, and a clan of tribes, and a tribe of communities, and a 
community of families—all these words implying different 
degrees of kinship. But the idea of kinship is not necessarily 
implied in the word nation or nationality, which is a political con- 
ception, a social integrate with a geographical home, and some 
measure of psychical unity. A unified nationality may include 
several distinct races, but in some cases, such as the Swedes, race 
and nation are almost convertible terms. It is plain, however, 
that kinship groupings, with which ethnology deals, must be dis- 
tinguished from political and social groupings. 

The making of numerous races depends, first of all, on man’s 
inigratory tendencies, and the question rises why mankind has 
spread over all the earth. Even in prehistoric times man has 
gone practically everywhere. ‘There were Morioris in New 
Zealand before the Maoris; the American Indians were preceded 
by the “Mound Builders”; there has always been some one before 
Columbus; and the question is why man is “the most wide-rang- 


99 


ing of all mammals.” The answer must be found in his big brain 
—always restless, ever adventurous, able to adapt life to circum- 
stances and to force Nature into service. But we must look for 


spurs to adventure in the ever recurrent pressure of increased 


1100 The Outline of Science 


population, and in the frequent changes of climatic and other 
environmental conditions. Man is not a very prolific organism, 
but parental care is strong and effective, and a little one soon 
becomes a thousand, and a small band a great nation. The 
pressure of increasing population may be checked by infanticide, 
or by a very high death rate; perhaps the keener spur was an 
environmental change, such as the setting in of aridity, which 
made “trekking” imperative. As Ellsworth Huntington and 
others have shown, climatic changes and diversities have had a 
profound effect on human evolution: they prompt migration, 
they insist on initiative, they sift and wimnow, and perhaps they 
stimulate variability. The old view that in a new climate men 
acquired new “modifications,” which were entailed as racial 
characters, is not readily tenable. In the new country new 
germinal variations crop up, and there is an elimination of the 
relatively less fit variants. It is indirect rather than direct adap- 
tation that we see in the establishment of races. 

Wandering is prompted by the adventurous spirit, by pres- 
sure of increasing population, and by climatic changes. Adap- 
tive varieties arise. But we cannot leave out of account the 
conflict of races, which has gone on through the ages almost with- 
out ceasing. Diffusion and spreading may mean at first nothing 
more than Man versus Nature, but sooner or later they involve 
Man versus Man. Over and over again a “superior” race has 
ousted an “inferior”; over and over again the victory in the long 
run has been with the conquered. It would be preposterous 
within brief limits to try to estimate the relative importance of 
the various forms of the human struggle for existence, but it is 
idle to deny that the conflict of races has been one of the sieves 
of mankind. 

Diffusions, migrations, raids, conquests, colonisations bring 
about intermingling or hybridisation. In regard to the profitable 
limits of this, we know little. The union of races, having 


markedly different characteristics, is apt to be disappointing. 


Ethnology 1101 


Hence the popular prejudice against the “half-breeds.” Drs. 
Kast and Jones have put the case biologically: 


Through the operation of the laws of heredity such unions 
tend to break apart series of character complexes which 
through years of selection have proved to be compatible with 
each other, and with the persistence of the race under the 
environment to which it has been subjected. Because of the 
transmission of factors in linked groups, the low probability 
of obtaining a single recombination equal or superior to the 
average of the latter race does not warrant the production 
of multitudes of racial mediocrities, which such a mixture 
entails. 


But there is another fact, which history seems to verify, that 
very good results follow the intermingling of peoples who are 
unlike but not too unlike. Thus Great Britain is inhabited by 
a very variable people whose blood includes contributions from 
many diverse Nordic Aryan stocks. Similarly the so-called 
Jewish race is made up of complex crosses. The moral is that in 
a strong nation the mingling of good stocks is promiseful. 


Ethnology and Population 


There is diversity of fertility in different races, and this has 
operated as a factor in evolution. There has always been a 
“yellow peril,’ or—of some other colour. As a matter of fact, 
the yellow races are not at present increasing very rapidly in 
numbers, for while their fecundity is high, so is their death-rate. 
Similarly in the United States the rate of increase of the blacks 
is not equal to that of the whites, for the death-rate among ne- 
groes is high. It is plain that differential fertility—greater in- 
crease in some races than in others—must lead to struggle in 
many forms, prompting wars, migrations, and colonisations, 
leading to social unrest and distress, and sometimes profoundly 
affecting the current moral sentiment. For it is very interesting 
to observe in contemporary evolution how economic conditions 


1102 The Outline of Science 


lead naturally to polygamy in one tribe and to polyandry in 
another, to exposure of female infants in one region and to their 
welcome in another. 

But beyond the problem of differential fertility, there is that 
of the possible over-population of the globe. Every year some 
forty million persons die, but far more than that are born! It 
has been estimated that the human population is at present about 
1,700,000,000, about a third of these being white. In most of 
the older civilised countries there has been for some years a de- 
cline in the birth-rate, but there is also a notable lowering of the 
death-rate. As civilisation develops the length of life will be 
increased and the health-rate will be heightened. ‘The world 
will become too full, though prophetic statisticians differ con- 
siderably as to the date of the tight-fit. 


The population question [said Huxley] is the real riddle of 
the Sphinx, to which no political Gidipus has as yet found an 
answer. In view of the ravages of the terrible monster, 
over-multiplication, all other riddles sink into insignificance. 


There are two suggestions, however, which must be considered. 
The first is that science is rapidly increasing man’s mastery of 
the resources of Nature. In many a field he can reap a richer 
harvest every year, and at less cost. The limits of this are un- 
known. The second suggestion is increased birth-control in its 
most enlightened forms. 


Must Races Decline? 


There is no one answer to the difficult problem of the decline 
and fall of races. (1) Sometimes there may have been a hope- 
less contest with a relatively fitter civilisation, especially when 
that included entirely new weapons, appliances, diseases, and 
luxuries. It is not necessary that the contact of the old and new 
should involve a malevolent conflict. Even pacific unconforma- 
bility may be fatal, as the modern story of some Central African 


Ethnology 1103 


tribes clearly shows. (2) Sometimes, perhaps, an aggressive 
and insurgent sub-race, or, more usually, a nationality, may out- 
step itself in militarism, may suffer too severely from an elimina- 
tion of its best men, and may be overwhelmed by hordes of push- 
ing and populous newly integrated peoples, naturally, and not 
altogether unjustly, called barbarians. Even Julius Cesar com- 
plained that there was beginning to be a lack of men. (3) Some- 
times, perhaps, the damning factor has been a slackening of 
morale, an insatiable love of luxury and ease, a slackening of 
the biological ideal of good stock and happy families, a relapse 
into the prosaic, the Epicurean, and the flabby. For lack of 
vision, as well as for lack of knowledge, the people perish. (4) 
Sometimes, we think, the fatal blow has come from “the hand of 
God’’—a succession of arid seasons, which has happened often, 
a failure of agricultural and pastoral industry, a dismal turning 
of fruitful land into desert—and then came the desperate trek- 
king, often, if not oftenest, a tragedy, though sometimes 
eventually a great success. Or it might be that “the hand of 
God” expressed itself in the introduction, in the normal course 
of events, of a new terror—such as a new parasite. So, accord- 
ing to some authorities, the introduction of the malaria-dissemi- 
nating mosquito into Greece brought about the waning of that 
glory. And everyone knows how modern races allow them- 
selves to be victimised by avoidable parasitic diseases, just 
as “‘the heathens,” more excusably, submit to Hookworm and its 
horrors. 

Yet it does not seem to be biologically necessary that a race 
should decline and die out. On the animal genealogical tree 
there are many branches that have been dead for millions of 
years. ~The fossil-bearing rocks—the great graveyards of 
the buried past—are full, not only of ancestors, but of lost races. 
Yet there are many very ancient races of animals that are go- 
ing strong to-day; and there seems no reason why this should 
not hold true for human races also—-provided that the survi- 


1104 The Outline of Science 


val value of health and vigour of body and mind is practically 
recognised. 


BIBLIOGRAPHY 


Cropp, E., Story of Primitive Man. 

Conxuin, E. G., The Direction of Human Evolution (London, 1921). 

Denixer, J., The Races of Man (Contemporary Science Series). 

East, E. M., anp Jones, D. F., Inbreeding and Outbreeding, their Genetic 
and Sociological Significance (Philadelphia and London, 1920). 

Gomme, G. L., Ethnology in Folklore (1892). 

Grant, Manison, The Passing of the Great Race (New York, 1918). 

Hasertannt, M., Ethnology (The Temple Primers, London, 1900). 

Huntineton, Eviswortn, Civilisation and Climate (New York, 1915); The 
Climatic Factor (1914); The Pulse of Asia (1907). 

Keane, A. H., Ethnology (Cambridge, 1906) and Man, Past and Present. 

Keirn, Sir Artuur, The Differentiation of Mankind into Racial Types 
(British Association Address, Bournemouth Meeting, 1919). 

Letourneau, Sociology based upon Ethnography (1881). 

Seret, The Mediterranean Race (Contemporary Science Series). 

Tay or, Isaac, Origin of the Aryans (Contemporary Science Series). 

Tytor, Epwarp B., Anthropology (London, 1881). 


XXXVI 


THE STORY OF DOMESTICATED 
ANIMALS 


VOL. IV—16 1105 


a aa a. 
) fai duke 


THE STORY OF DOMESTICATED ANIMALS 


HE art of domesticating wild animals is one of immense 
1Q antiquity, carrying us back to a period long before 
written records were possible. So far as the evidence 
goes it would seem that the dog was the first of man’s conquests 
over Nature. And this was made towards the end of what we 
know as the Old Stone Age or Paleolithic period. Man was 
still a nomad and a hunter. But he had by this time developed 
the custom of burying his dead, and more than this, he would 
seem also by this time to have developed some vague notions, at 
least, of a future life; for when a man died his rude weapons, 
and his dog, were buried with him, as if to serve him in the land 
of shadows. It is to this custom that we owe our only evidence 
as to the period when the domestication of animals began. And 
since the dog only is found with these early interments we must 
conclude that it was man’s first companion and servant. Puppies 
brought home, perhaps, to amuse the children laid the foundation 
of what was to prove an immense aid to the evolution of civilisa- 
tion. 

With the succeeding Neolithic stage of culture, wherein the 
surfaces of the stone axes and other weapons were beautifully 
polished, the nomadic habit gave place to settlements, and the 
arts of Peace—pottery-making, weaving, and agriculture, and 
the possession of flocks and herds. The wild oxen, sheep, goats, 
and pigs by which these ancient men were surrounded all seem 


to have been laid under tribute almost simultaneously to fur- 
1107 


1108 The Outline of Science 


nish, from animals bred in captivity, a permanent supply of meat, 
milk, skins, and beasts of burden. 

Domestication during unnumbered thousands of years has 
done nothing to change these several animals in one respect, and 
this in the matter of the peculiarities of their flesh as food. For 
each has still its characteristic qualities and flavour. An ox, a 
sheep, and a pig, all reared in the same field and partaking of the 
same food, will yet, owing to the subtle and inherent differences 
in their nature, respond differently to their nurture. Yet in the 
matter of form, size, and rate of maturity these creatures, under 
man’s control, have undergone the most striking transformation. 
So much so that the various races of many of our breeds of 
domestic animals differ more from one another than do many 
wild species. Our various breeds of cattle, sheep, and pigs, dogs 
and horses, are all witnesses of this fact. ‘These are often cited 
as so many examples of the “breeder’s art,” as if the founder 
of any given breed had before him a definite conception, a power 
of visualising the ultimate development of the salient features, 
at any rate, of the breed he cherished. The breeder of the old 
English bull-dog could have had no conception of the bull-dog 
of to-day. It would have filled him with consternation, for the 
bull-dog, as we know it, would have been useless for the work 
which his ancestors had to perform. All that the breeder has 
been able to do is so to control the mating of his stock as to 
accentuate such variations from the normal as seemed to him, 
either from utilitarian or spectacular reasons, to be worth culti- 
vating. In his own day he sees but little real change. Only 
after some scores or hundreds of generations is there any 
striking advance on the type accepted by the earlier breeders. 


er 


Horses 


Our domesticated horses, there is good reason to believe, are 
descended not merely from more than one originally wild species, 


Photo. F. W. Bond. 


MONGOLIAN WILD HORSE 


' The ‘‘Tarpan,’’ from which the horses of Western Europe have been derived. 


Photo: Charles Reid. 


SHETLAND PONY 


The smallest of our native horses. How, and when, it gained entry into the 
Shetlands is unknown. 


‘fects et: A: 


Photo: W.A. Rouch. 


ARAB STALLION 


It was from Arab sires mated with native English mares that our ‘‘thoroughbred’”’ was derived. 


The Story of Domesticated Animals 1109 


but from two distinct stocks. One of these, which flourished 
during Pliocene times, was a slender-limbed species, standing 
about 15 hands high, and having a broad forehead and tapering 
face, and certain peculiarities of the molar teeth. This type is 
represented by the Siwalik horse (Hquus sivalensis). The Arab 
may be a descendant of this stock. The other dates from Pleis- 
tocene times, and is represented by a smaller, heavier, stout- 
limbed animal, surviving to-day in the Tarpan, or Mongolian wild 
horse (Hquus przevalskyi). This view is supported by the strik- 
ing likeness of the prehistoric carvings of horses of Stone Age man 
which have been found in the haunts of Cave Man in France and 
elsewhere. During prehistoric times, however, it was apparently 
represented by more than one species. The survivors to-day ap- 
pear to be the Mongolian horse of the Gobi Desert, just referred 
to, and the “Celtic pony,” represented by a race of small horses 
or ponies, ranging from Connemara, the Outer Hebrides, Ice- 
land, and the Feroes, to Western Norway. 

While it is generally held that, with the exception of the 
dog, man possessed no domesticated animals until Neolithic 
times, and that the horse was the last of his conquests, it must be 
remembered that engravings of horses’ heads wearing a rope- 
like halter have been found, which were certainly the work of 
men of the Paleolithic period. Yet during these times—in 
favoured localities perhaps—the horse formed one of the staple 
articles of diet. ‘This much is shown by the refuse heap .dis- 
covered outside the celebrated cave, or rock-shelter, of Solutre. 
This could scarcely have accommodated more than half-a-dozen 
families, but the entrance was protected by two walls of horse- 
bones, one 150 ft. long and 10 ft. high, the other 40 ft. long and 
5 ft. high, representing, it is estimated, the remains of some 
100,000 horses. The man who engraved the horse’s head with the 
bridle, an Aurignacian, also added his share of victims to this pile. 

That the horse was domesticated in Neolithic times there is 
no room for doubt, though whether used as a riding animal or 


1110 The Outline of Science 


as a beast of burden is not known. It may be that it was first 
domesticated for the sake of its flesh and milk; then as a beast of 
burden-—pack-horse—and still later as a draught animal. But 
though during all this time isolated peoples may have used 
horses for riding purposes, it is significant that the Ancient 
Egyptians and Assyrians, the Ancient Greeks and Romans, and 
the Ancient Britons used them to draw chariots, and not as 
riding animals. 


British Breeds 

This is not the place for a detailed description of our British 
breeds of horses. Suffice it to say that the oldest of these is rep- 
resented by the Shetland, Welsh, New Forest, Dartmoor, Ex- 
moor, and Connemara ponies. In the South of Scotland, a 
larger type, known as the Galloway, is found. From the larger 
types of these ponies the old pack-horses of the South of Eng- 
land were bred, and these were also largely used for riding. The 
‘magnificent carriage-horse known as the Cleveland bay hails from 
the North Riding of Yorkshire. Of its early history nothing is 
known, but it is believed to have been produced by crossing horses 
of foreign blood with the native stock of the district. Nearly akin 
to this is the Yorkshire coach-horse, an animal of rather more 
slender build. Unfortunately both these breeds are threatened 
with extinction. 

Among the English heavy breeds perhaps the most famous 
is the Shire-horse, the Great Horse of Medieval England. Ac- 
cording to some this breed was derived from the chariot-horses 
of the Britons of Cesar’s time. 

The slightly smaller Clydesdale represents the Shire-horse 
in Scotland. It is a comparatively recent breed dating back to the 
importation in 1715 of a Flemish stallion, which was crossed with 
native horses. 

The Suffolk Punch is a famous and very distinct breed, and 
readily distinguished from either of the foregoing breeds, having 


The Story of Domesticated Animals 1111 


a large head, short, arched neck, low and heavy shoulders, straight 
back, and short limbs. It is a very powerful animal, but suitable 
only for farmwork. As to its origin nothing certain is known, 
but it is believed to have been carried from Normandy centuries 
ago into the Eastern counties of England. 


The Arab 

As to the Arab: this type, as already mentioned, represents 
an older stock than that of the “cold-blooded”? Western horses, 
since it is apparently descended from the Indian, Pliocene, Siwalik 
horse; and in consequence, it has been claimed, it should rank as 
a distinct species. But be this as it may, the part played by this 
animal in the history of the evolution of domesticated horses is one 
of profound importance. For it has been proved beyond cavil 
that there is hardly a breed of our Western horses which has 
not been immensely improved by an infusion of Arab blood. 

During the time of the Crusaders, Arabs, Barbs, and 'Turks 
—the two latter being derivatives of the Arab—were from time 
to time introduced into England, and these importations were 
continued at intervals and aimlessly, up till the time of James I. 
From this time till Anne’s reign—just 100 years—Arabs, Barbs, 
and Turks were imported in considerable numbers for the set 
purpose of improving our native race-horses. The sires of the 
earlier importations were mated with native English mares, 
and it was the progeny of these unions which laid the foundations 
of our “Thoroughbred” or “Race-horse’—a peculiarly English 
creation, though now scattered all over the world. 

But more than this. Throughout all this time ‘“thorough- 
bred” sires have been persistently used for the purpose of 
improving the qualities of ponies, carriage-horses, and riding- 
horses, as well as of the heavier breeds. It is for the preservation 
of this refining stock that we need our race-courses to-day. 

The domestic Ass is a direct descendant of the North Afri- 
can Wild Ass (Hquus asinus africanus), from which it differs 


1112 The Outline of Science 


but little in appearance and coloration, though some breeds are 
black and some white. The largest of all domesticated asses is 
that of Poitou, some specimens of which rival cart-horses in point 
of size. In Spain, as in the East, ass-breeding is carefully 
studied, and this has resulted in the development of a number of 
distinct types, finer in appearance and of greater utility than any 
found in England, where it is never used for riding purposes, save 
for children, or in farm-work. But with us, and indeed wherever 
it is met with, its milk is valued. In ancient times, in the East, 
herds of she-asses were kept solely for the sake of their milk. 

The Mule is, properly, the product of the cross between the 
male ass and the mare. The product of the converse cross—be- 
tween the stallion and the she-ass—is known as a “hinny.” In 
the British Islands mules are as a rule very little used, but in 
Spain they are prized on account of their sure-footedness in 
mountainous country. They are largely employed in the Pun- 
jab frontier districts for military purposes, where mule batteries 
for hill-work are needed. (During the late war large numbers 
were also imported into this country to be used on the various 
fronts for military transport purposes.) In addition to their 
sure-footedness, mules, in proportion to their size, are stronger 
and more enduring than horses; like the ass, they will also thrive 
on poorer fodder and are less liable to disease, and they are 
further said to be longer lived. As is commonly the case with 
hybrids between very distinct species, neither mules nor hinnies 
are fertile, consequently no new breeds are possible. 


§ 2 


Cattle 


It is worth remembering that the earliest known British 
domestic cattle, which date back to Neolithic times, are of an 
alien breed—the Celtic shorthorn (Bos longifrons). The origin 
of this breed is unknown, for it has nowhere been found—and its 
remains are scattered all over Kurope—save as a domesticated 


Photo: W. A. Rouch. 


PERSIMMON (taken immediately after winning the Derby, 1896). 


He also won the St. Leger in 1896, and the Ascot Gold Cup and the Eclipse Stakes in 1897. His sire was St. Simon, his dam Perdita. 
His owner was King Edward VII. 


Photo: Charles Reid. 
HIGHLAND COWS 


The West Highland, like the Pembroke cattle, are indigenous to Great Britain, and of great antiquity. 


Photo: F. W. Bond. 


A DOMESTICATED FORM OF THE WILD YAK, FOUND ONLY IN THE RUSPU PLATEAU 


The wild animal is larger, and has longer horns. 


The Story of Domesticated Animals 1113 


animal. And it remained the only domesticated ox, so far as the 
British Islands are concerned, until the coming of the English, 
500 years after the birth of Christ. These new settlers, it would 
seem, either brought with them a new breed, derived from the 
great wild ox, or Aurochs, of Europe (Bos primigenius) , or they 
gathered to themselves herds from the wild Aurochs which they 
found in the vast woods which still covered the country. But 
be this as it may, it is from this stock that most of our native 
breeds of to-day are descended. 

At one time it was firmly believed that the famous white 
“Park cattle,” of which the best known are the Chillingham and 
Chartley herds, were the lineal descendants of the Aurochs. 
To-day they are held to be extremely ancient descendants of one 
of the many domesticated breeds which can be directly traced to 
this source. The black Pembroke cattle or “Welsh runts,” the 
black or red Highland cattle or “Kyloes,” and the “long-horned,”’ 
are the most famous of the breeds which man has, so to speak, 
fashioned out of the original stock—the wild Aurochs. 

Careful selection on the part of the old-time breeders has 
brought about the evolution of three distinct types of our British 
domesticated cattle—beef-producing, dairy cattle, and draught 
animals. Of the first-named type the Shetland would stand 
easily first but for its small size, since it attains to maturity 
earlier than any other of our British breeds of cattle, and as 
“beef” it is unsurpassed. ‘This breed also furnishes some wonder- 
ful milkers. Kerry cows are famous, yielding, in proportion to 
their size, more milk than any other British breed. But most of 
our dairy cattle are represented by “Dairy shorthorns.” 

While the Celtic shorthorn and the Aurochs have furnished 
the stock from which our British breeds of cattle have been 
derived, on the Continent a number of very distinct breeds are 
found, which have been derived from the Indian humped cattle 
which, in turn, are descended from the wild Malayan Bantin 
(Bos sondiacus). 


1114 The Outline of Science 


The large, dun-coloured Podolian and Hungarian cattle 
with enormous horns, and the similar cattle of northern Spain, 
are derived from humped cattle, and are used largely for draught 
purposes and agriculture. The Castilian and Andalusian bulls, 
and those of the Navarra breed, used in bull-fights, are appar- 
ently descended from the Aurochs. 

The Indian humped cattle differ from the European cattle 
in the great fleshy hump on the withers, which may weigh as much 
as 40 or 50 lb., and is esteemed a great delicacy in India. 
Furthermore, they display an enormous dewlap, and the voice 
is a grunt rather than a low. Commonly the humped ox is known 
as a “Zebu,” a word of unknown origin and never used in India. 
These animals, in India, commonly take the place of horses. 
Some breeds, like the Hissar cattle of the North-West Provinces, 
have enormous horns and drooping ears. 

The native cattle of Africa are the humped races, though 
some, like the Uganda cattle and the famous Cape Trek-oxen, 
have lost the hump. In these, and the Nuer cattle of the Kastern 
Sudan, the horns often attain a huge size. 

Very different from any of the wild oxen so far mentioned is 
the great Indian buffalo, or Arna, standing 6 ft. at the withers, 
and with enormous outstanding horns. Domesticated breeds 
of this animal are used by the natives throughout India, Ceylon, 
and the Malay States. The Todas, of the Nilgiri hills of Madras, 
keep enormous herds of these buffaloes for the sake of their milk 
and butter. In many parts of the plains they are mainly em- 
ployed for agricultural operations, and as beasts of burden. 

The last of the wild oxen which have been brought under the 
yoke of man is the Yak of Tibet, the nearest living relative of 
the Bison. It is used both as a beast of burden and as a 
riding animal, while it also furnishes food and clothing to the 
hardy natives. It has also been introduced into parts of 
Siberia: here as in Tibet, travel without its aid would be an 
impossibility. 


The Story of Domesticated Animals 1115 


§ 3 
Sheep 

They were great benefactors of mankind who first domesti- 
cated the sheep; but we can raise no monument to their memory, 
for we know no more than that they lived in Neolithic times. And 
the difficulty of any effort to-day to identify these benefactors is 
immensely increased by the fact that the gentle art of shepherd- 
ing was acquired in two widely sundered regions. ‘This much 
seems certain, since our existing flocks give proofs of a deriva- 
tion from two very distinct stocks—the Mouffion of Europe (Ovis 
musimon) and the Asiatic Urial (Ovis vignet) ; and he would be 
a bold man who would venture to say whether the Kuropeans or 
the Asiatics were the first flockmasters. 

But man has done more than domesticate the sheep. He has 
transformed it to a much greater extent than is the case with 
cattle or the horse. ‘To-day we think of sheep in terms of wool— 
to us it is before all else a woolly animal. But this is not the case 
in the wild sheep, which appears to be as hairy as an antelope or a 
goat; but under the superficial hairy coat is an “under-fur” as in 
many other animals, like seals for example. During long ages 
of domestication this under-fur has been developed so that only 
the face and legs retain their original covering. Two other 
changes have resulted from domestication: the brain has greatly 
decreased in size as compared with wild sheep, and the tail has 
greatly increased in length, so much so that “docking”’ has become 
imperative in nearly all breeds. But some breeds of domesticated 
sheep have no wool, such, for example, as the African Long- 
legged sheep and the Abyssinian maned sheep. 

By way of contrast we may take an example or two from 
among the “woolly” breeds wherein the wool has been enormously 
developed, as in the Merino and the Scottish black-faced in which 
the fleece reaches to the ground. But the wool of the last named is 
of more use for carpet-making than for cloth-making. 


1116 The Outline of Science 


It is difficult to imagine to-day how the civilised world con- 
trived to rub along without wool, but when and where man first 
conceived the desire to cultivate its growth we shall probably 
never know. It began, we may suppose, among people who used 
skins for clothing, and these would be people living where the 
winters were severe. This factor, the stimulus of cold, would of 
itself induce an increased development of the under-fur where, as 
in the sheep, it already existed. When the primitive herdsman 
discovered that such skins were warmer than the normal hairy 
skins, he would speedily set himself to breed only from such of 
his flocks as promised the woolliest coats. 

A very remarkable kind of wool is that of the Bokharan or 
Astrakhan dumba sheep, the very young lambs of which furnish 
the much prized “fur” known as Astrakhan. It is a native of 
Bokhara and the Kirghiz steppes and of Persia. 

Though most of our British breeds of sheep are now hornless, 
some, like the Norfolk, Dorset, and Scottish sheep, have really 
magnificent spiral horns. In the matter of these weapons, in- 
deed, sheep have, under domestication, developed some very re- 
markable features. For some, like the St. Kilda sheep, have 
increased the number from one to as many as three pairs, while 
in the Wallachian sheep they take the form of extremely long 
spirals, looking like gigantic corkscrews. 

The tail of the domesticated sheep, it has been pointed out, 
is always longer, sometimes considerably longer, than in wild 
sheep, and in some breeds it presents a further peculiarity in that 
it becomes loaded with fat till it may attain a weight of as much 
as 40 lb., as in the common sheep, which is kept also by the Arabs 
(who regard it, fried in slices, as a rare delicacy). In this animal 
the tail does not reach below the hocks, but it is of great breadth, 
measuring as much as a foot across. But in the Cape fat-tailed 
sheep it is much longer and may trail on the ground: it never, 
however, attains to the width seen in the Syrian sheep. 

The opposite extreme, in this matter of tails, is found in a 


Photo: British Museum (Natural History) 
WALLACHIAN KAM 


This remarkable breed is found only in Hungary and N.W.China. 


Photo: British Museum (Natural History) 
SOA (SOAY) EWE, ST. KILDA 


This is a very small and primitive type: the rams stand only about 24 inches at the shoulder, 
and the ewes are still smaller. 


Photo: British Museum (Natural History). 


FOUR-HORNED MANX LOAGHTAN RAM 
Related to the Shetland breed. They are very small, and this is due to the fact 


that they are found only on the hill-tops where the soilis poor. On English pasture- 
lands they increase in size. 


4, 


alarsetitaebartarmeniensaned 


Ee 


Photo: British Museum (Natural History) 
UNICORN BARWAL RAM, NEPAL, INDIA 


The apparently single horn is really formed of two distinct horns, which are artificially 
pressed together by the native breeders. 


The Story of Domesticated Animals 1117 


large, lop-eared sheep ranging from southern Siberia to the Kir- 
ghiz steppes, wherein the tail is reduced to a minute vestige, while 
an enormous accumulation of fat is developed on the hind-quar- 
ters, weighing from 30 to 40 lb. This fat, semi-fluid and butter- 
like, constitutes the great bulk of Russian tallow. The fat “rump” 
of sheep used by the Israelites in sacrifices seems to show that in 
Biblical times fat-rumped sheep were kept in Palestine. These 
sheep, by the way, are singularly coloured, the head, neck, and 
legs being black, and the rest of the body white. They are also 
hornless. 

Our British sheep are commonly divided into Long-woolled, 
Down, and Mountain breeds. But this leaves out of account one 
of the most interesting, because the most primitive, of all. This 
is the little animal known by the uncouth name of Loaghtan— 
“mouse-coloured’’—of the Isle of Man. This at any rate is the 
type. But very similar sheep are found throughout the Outer 
Hebrides and in Soay, in the St. Kilda group, the Shetlands, and 
north yet to the Feroes and Iceland. Three features distinguish 
the sheep of this type—small size, short tail, and brown coloration. 
Further, there is a tendency to increase the number of horns, of 
which there may be as many as three pairs. 

For the most part sheep are kept for the sake of their wool, 
flesh, or milk, while the skin is used for parchment. But there is 
a tall, long-legged sheep known as the Hunia, which is used for 
carrying salt and borax over the Himalayan passes. Both sexes 
are horned, and in the male there may be four horns. Another 
Himalayan sheep, known as the Barwal sheep—a near relation of 
the Hunia, but shorter-legged—is used in the Punjab and other 
parts of India as a fighting sheep, being pitted in combat either 
with its fellows or with other animals. This is the fighting ram 
of India, and displays remarkable courage. The shock with 
which two rams meet is astounding, the sound of the impact of 
their heads being audible at a distance of two or three hundred 
yards. 


1118 The Outline of Science 


Finally, because showing how amenable to domestication the 
sheep has proved, it must be mentioned that in some of the Ork- 
neys, where no other provender exists, the little sheep of the 
Loaghtan type are fed upon fish which are dried upon the rocks 
for that purpose. By way of a change of diet they will make 
their way down to the sea at low tide for the purpose of feeding 
upon seaweed. 


Goats 

Let him who talks glibly of “separating the sheep from the 
goats” essay his hand at the attempt, and he will find that he has 
undertaken a task several sizes too large for him. At any rate 
the man of science has not yet succeeded in achieving this feat. 
The matter is not easy even when domesticated animals alone are 
concerned, but when a sharp line has to be drawn between wild 
sheep and wild goats the difficulties become insurmountable. But 
since we are concerned here only with the domesticated goat no 
useful purpose would be served by discussing the nature of these 
difficulties at length. 

The earliest known domesticated goat, it is to be noted, is 
obviously derived from the existing wild goat (Capra egargus) 
of the Mediterranean isles, Asia Minor, and Persia. 

One of the most striking and most valuable of domesticated 
goats is the Kashmir or Tibetan shawl goat, which has developed 
a thick woolly under-fur, from which the famous Kashmir shawls 
are made. ‘This animal is kept in enormous flocks in Ladak and 
Tibet. It is a long-horned, lop-eared animal, and varies in colour 
from white to black. No less valuable is the Angora goat of Asia 
Minor. ‘This is a large animal, with long spiral horns, resembling 
those of the Markhor, and long, pendant ears—a foot long. But 
its value lies in its long, silky, white hair, which may reach almost 
to the ground and is used for the manufacture of a peculiar kind 
of cloth known as Mohair. Some authorities hold that this animal 
is a direct descendant of the wild Markhor. If this be so, then we 


The Story of Domesticated Animals 1119 


have direct evidence of the derivation of domesticated goats from 
two distinct wild stocks. 

The remarkable persistence to type which some breeds of 
domesticated animals display is strikingly illustrated by the 
Syrian and Theban goats, since both were cherished by the ancient 
Egyptians, who painted them in their frescoes and mummified 
their bodies. ‘Thus, then, we can say of a certainty that these 
two breeds are many thousands of years old, yet in all this time 
they have hardly changed! 

Under certain conditions the domesticated goat may become 
a really formidable animal, entirely changing the economic con- 
ditions of vast tracts of country. And this is owing to its prefer- 
ence for browsing on woody shrubs and seedling trees, rather than 
on grass like the sheep. As a consequence, even in the most de- 
serted parts of Palestine, they have destroyed the forests; and 
similarly they have devastated the Island of St. Helena. In other 
parts of the world cattle and the camel have wrought like destruc- 
tion, producing barren wastes where once flourished luxuriant 
forests. 


§ 4 

Pigs 

Cattle, sheep, and pigs, wherever we wander about the 
country-side, are always so intimately associated that it is diffi- 
cult to think of one without thinking of all three. And they have 
come to us thus linked together from the days of the Stone Age. 
One can hardly conceive it possible that the domestication of all 
three began simultaneously ; indeed, the evidence, so far as it goes, 
seems to show that the pig was the last of the trio to give hostages 
to man. But it would seem that man lost no time in adding to 
his responsibilities as a stock-keeper, when once he had appreciated 
the advantages to be gained by the possession of flocks and herds. 
How much of this choice was due to “intuition,” and how much to 


selection from a number of different animals kept for experiment, 


1120 The Outline of Science 


we shall never know. But he must have congratulated himself 
on his subjection of the pig, whose toothsomeness had long been 
known to him from the flesh of boars—and occasionally sucking- 
pigs—slain in the forests. 

Our domesticated pigs have been derived from two distinct 
stocks. The wild boar is the ancestor of the Northern Kuropean 
breeds, while those of Southern Europe, Asia, and Africa have 
been derived from one of the Malayan pigs, possibly the “collared 
pig” (Sus vittatus). 

It is surely not a matter for surprise that in the course of 
10,000 years or so of idleness and domesticity, one should remark 
a considerable loss, both of litheness and intelligence, as com- 
pared with their wild relations. The boars display a considerable 
degeneration in regard to the size of their still formidable tusks; 
while both sexes have developed a great facility for putting on 
fat, and this at the expense of their hairy coats. All wild pigs, 
when young, have longitudinally striped coats. This is never the 
case with domesticated pigs, but these have no need of such 
“camouflage.” Apart from the transformation due to fat, domes- 
ticated pigs have changed chiefly in the great increase in the size 
of the ears, and the very striking shortening of the face seen in 
breeds like the “Middle-white” Yorkshire and the Berkshire 
breeds. There is also a very remarkable breed of “solid-hoofed”’ 
pigs, in which the two front toes are enclosed in a single sheath. 
It now chiefly survives in America, where it is cherished under 
the belief that it is immune to swine fever, though there seems to 
be no very certain evidence that this is the case. Finally, all 
domesticated pigs seem to have developed a curious semicircular 
twist in the tail, for which no explanation has yet been offered. 


§ 5 


Dogs 
Those ancient hunters, the Azilians, apparently despised art, 
but they laid the foundations of tremendous events—the domesti- 


THE MASTIFF 


The Mastiff is, perhaps, the oldest of our British breeds of dogs. 
Its ancestors were flourishing in England before the time of Julius 
Cesar’sinvasion. But the Mastiff of the present-day show-bench 
has changed for the worse by the great shortening of his face. 


THE BULLDOG 


The Bulldog is an early descendant of the Mastiff. But since 
the days of “‘bull-baiting’’ he has undergone a drastic change of 
form, such as would have made him useless for the work performed 


by his ancestors. 


THE SCOTS DEER-HOUND 


The Scots Deer-hound is a very ancient breed, and its origin is 
obscure. Some authorities insist that it is an indirect descendant 
of the Irish Wolf-hound. 


THE WIRE-HAIRED FOX-TERRIER 


The Wire-haired Fox-terrier is a comparatively modern breed, 
since the evolution of the English terrier began only about 130 years 
ago. His ancestors, black and tan in colour, were very unlike the 
terrier of today—from the show-bench point of view. Then, as 
now, their real purpose was for ‘‘bolting’’ foxes. The terrier of 
today, whether wire-haired or smooth, is white with dark markings. 


Rion Bea cde Rea 


Photo: Sport and General. 


me seo 


THE BLOOD-HOUND 


The Blood-hound is descended trom the St. Hubert, a breed of 


great antiquity. 


The Blood-hound in modern times has under- 


gone a great transformation in regard to the modelling of the head 


and face. 


THE COCKER SPANIEL 


The Cocker Spaniel isa very old breed. From it is derived the toy 
spaniel. It was originally bred for woodcock-shooting. 


The Story of Domesticated Animals 1121 


cation of animals. True, they got no further than the mastery of 
the dog to aid and abet them in their hunting; perchance because 
already their game was growing scarce, and more wary, from 
constant harassing. But this conquest over wild Nature was a 
great beginning, and there can be no doubt but that it had a pro- 
found influence over man’s future destiny. [Tor 7,000 years— 
unfortunately we cannot fix the precise date when the first dog 
pulled down the first deer at his master’s bidding—the dog has 
been man’s most intimate companion and servant. 

That first “dog,” we may be almost certain, was a wolf.. 
Later, there is good evidence to show, the jackal was in like 
manner enlisted. From these two stocks our dogs of to-day are 
descended. Bearing this in mind we shall the more easily ap- 
preciate the almost infinite variety which confronts us in any 
survey of the breeds of dogs which the records of the past, 
and of the modern show-bench, have preserved to us. 

In using the term “wolf,” it should be remarked that it 
includes not only the European wolf, but also the Indian wolf 
(Canis pallipes) and the North American Coyote (C. latrans). 
When immigrants from the East settled down to form the 
earliest Swiss lake-dwellings during the Stone Age, they 
brought with them dogs derived from the Indian wolf, and these, 
no doubt, must have hastened the evolution of new types by 
crossing with the Azilian dogs derived from the European wolf. 

The desire to raise a strain of dogs for some special pur- 
pose, or to satisfy the love of developing mere freakishness, has 
indeed borne fruitful results: inasmuch as we can now recognise 
no fewer than six distinct types—the Wolf-like group, Grey- 
hound group, Spaniel group, Hound group, Mastiff group, 
and Terrier group. Among the Wolf group we have Eskimo 
dogs, Sheep-dogs, Collies, and the Pariah dogs of Eastern 
Europe, Asia, and Africa. Among the Greyhounds the 
English and Italian greyhound, Deerhound, Irish wolfhound, 
and the great Borzois. .The Spaniels include giants like the 


VOL. IV—I7 


1122 The Outline of Science 


Newfoundland, and dwarfs like the useless little Pekinese and. 
Japanese spaniels, as well as the Field and Water spaniels. 
Bloodhounds, Staghounds, Foxhounds, Otter-hounds, Dachs- 
hunds, Pointers, and the Dalmatian carriage hound represent 
the Hound group, wherein the power of scent is developed in 
a remarkable degree. 

A long list of names such as this does not make very enter- 
taining reading. But con it again and reflect that it stands for 
man’s achievements in the manipulation of flesh and blood during 
some 7,000 years, and it at once assumes a new significance. 
Read it again, trying to visualise the appearance of these ani- 
mals. Kskimo dogs, sheep-dogs, collies, and Pariah dogs. 
Eskimo dogs, trained to draw strange-looking fur-swathed people 
in sledges over the snow. Collies and sheep-dogs rounding up 
flocks of silly sheep with a skill surpassing that of man himself. 
Think of the bond of sympathy between the master and servant. 
Pariah dogs, outcasts, every man’s hand against them, yet 
contriving to hold their own in spite of buffetings, in sun- 
scorched Eastern streets. Look at the lithe and graceful grey- 
hound, kept for no other purpose than to course hares during the 
chill, short days of winter. His forbears, “‘prick-eared” but 
otherwise not very different, were cherished by the ancient Kgyp- 
tians, embalmed when they died, and portrayed in vivid colours 
on monuments. 'To serve the ends of sport alone, man has cre- 
ated, so to speak, an almost bewildering number of breeds; and 
the behaviour of some of these demonstrates a high degree of 
canine intelligence, as for example in the case of the retriever 
and the pointer. 

The St. Bernard, a near relation of the great Newfound- 
land, has been assigned another role. His part is to discover and 
succour the lost in deep snow-drifts on terrible mountain passes, 
whereat he has won fame imperishable. 

There are few dogs which do not inspire affection; many 
crave it. But there are some which seem to repel us, like 


The Story of Domesticated Animals 1123 


the bloodhound. True, man has made him what he is. 
Terrible to look at and terrible to encounter, man has raised 
him up to hunt down his fellowman. Hence the poor beast 
is shunned alike by innocent and guilty. But, as a_ pro- 
duct of man’s capacity to guide, if not to control, the evo- 
lution of a given type, the bloodhound is really a remarkable 
animal. 


Selection in Breeding 

As a witness to the subtle and sub-conscious directness of the 
human mind the evidence furnished by the domesticated dog is 
valuable indeed. By careful selection of his breeding stock and 
shrewd matings, man has, so to speak, inveigled Nature to fashion 
for him just the kind of dog he wanted for a particular purpose. 
In make and shape and temperament he has contrived to attain 
very near to his ideal. And this is as true of the dogs which he 
has brought into being, as with a magician’s wand, to please his 
fancy for freakishness, as well as of those desired to satisfy his 
needs. The bulldog of the show-bench—which is a modern inno- 
vation—well illustrates this point. His prototype, bred for the 
barbarous and singularly brutal sport of “bull-baiting,”’ bore 
but a slight likeness to the animal known as a bulldog to-day. 
This poor creature, heavy-bodied, bow-legged, and “under- 
hung,” unable to walk a mile, and with defective breathing- 
passages and bad teeth, would have been absolutely useless in 
the bull-ring. His only merit to-day lies in his ugliness. It has. 
taken something like a hundred years to bring this animal to its 
present state of “perfection,” and the only useful purpose which 
can be urged for this expenditure of mental energy on the part of 
his “creators” is that it shows what can be done in the direction of 
evolving new types by persistently breeding from animals which 
promised to show exaggerations of certain salient features pleas- 
ing to the capricious fancy of the devotees of the breed. And 
what is true of the bulldog is true also of “lapdogs” like 


1124 The Outline of Science 


Pekinese, pug-dogs, and the little woolly doormats known as 
Maltese terriers. 

And now a word as to “Edible dogs”! ‘To the Western mind 
this sounds a repulsive form of food. ‘To-day the principal dog- 
eaters are the Chinese, who keep the “Chow-chow”’ for this pur- 
pose, and the natives of the Society Islands. The natives prefer 
dog to pork, and if we are to believe Captain Cook, between a 
South Sea dog and English lamb there is little to choose! ‘The 
Eskimo have a fondness for foxes, which the Stone Age people 
also apparently regarded as a delicacy. Hence it seems that the 
taste for dog-flesh is a very ancient one. 


6 


Cats 


Stone Age man boasted no “household”: hence he had no 
cat. For the domesticated cat is before all things a “household” 
animal, living idly, and rendering no service for the shelter af- 
forded, save catching an occasional mouse—for sport. 

When civilisation had, so to speak, got into its stride, and 
man had an abiding resting-place, and started keeping “pets,” 
the cat appeared. When its domestication actually began we do 
not know, but it had very definitely established itself with the 
ancient Egyptians of the XX Dynasty, that is to say about 1,000 
B.c. So much so that it had come to be regarded as a sacred 
animal and was embalmed at death, as witness the mummied cats 
in the British Museum. 

Cats are far more stereotyped creatures than dogs. That 
is to say, they are by nature prone to go on, generation after 
generation, with an almost machine-like precision in regard to 
their structural characteristics; and hence they offer no new 
features upon which the breeder might seize for the development 
of new types. This much is shown by the fact that after some 
3,000 years of domestication we have still very few distinct breeds 
of cats. ‘True, there are the tabby, and the tortoise-shell— 


| 
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ODE NWA. ave ei favre acces scar an CTEM TORT TCT AT NT ie eev on 


THE EVOLUTION OF. DOMESTICATED PIGEONS 


All the varied races of domesticated pigeons have been derived from the wild Rock-Dove or ‘‘ Blue-rock,’’ asa result of ‘‘selection”’ 
on the part of the fancier. That is to say, during long centuries, by seizing now upon this and now upon that exaggeration of some 
particular feature, or upon some chance variation, and mating with others showing a like departure from the normal, totally distinct 


races have been brought into being. 


Reading from left to right: PouTEeRs; Fan-TaiL_s; Rock-DOVE; CARRIER; JACOBIN; ANTWERP and TURBIT. 


The Story of Domesticated Animals 1125 


which are nearly always females—black cats, and white cats; 
long-haired cats, strangely coloured Siamese cats, and cats with 
“bob-tails.”” But they are all cast in the same mould, differing 
only superficially; and this even though descended from several 
distinct but closely related wild ancestors, of which the Egyptian 
wild cat may be taken as the type. 

There is one point about our domesticated cats which is not 
only extremely interesting but also very puzzling, and this con- 
cerns the pattern of the coat, which presents two quite distinct 
types. In the one the head is longitudinally and the body trans- 
versely striped, after the fashion of the European wild cat and 
the Egyptian cat. In the other the body is marked by broad 
bands, roughly spiral, on the flanks. This type represents the 
true “tabby”: the word having reference to the well-known 
pattern of “watered silk.” Cats of all colours may be thus 
marked. Even when the two types are crossed the several 
members of the litter will present both types but no suspicion of 
blending—some will be striped and some will be “tabbies.”” No 
explanation of these very striking differences seems possible. 


§ 7 


Rabbits 

We are dealing in these pages not so much with domesticated 
- animals as with the domestication of animals, for this is an Out- 
line of Science dealing with principles rather than with details. 
In considering domesticated rabbits, for example, it is a matter 
of no profit to know the names of all the numerous breeds of 
these animals—that information concerns the “fancier” and 
even he generally confines his attention to one or two breeds. 
Rather we are concerned with these questions. Firstly, why were 
rabbits and not hares domesticated? And secondly, how is it 
that the species Lepus cwniculus—the common wild rabbit—has 
come to be the ancestor of our tame rabbits rather than any one 
of a number of other species of wild rabbit? More than this: 


1126 The Outline of Science 


one is tempted to ask how came there to be domesticated rabbits 
at all? 

No definite answer can be given to these questions. But 
we may imagine that when once man discovered the many and 
great advantages that would follow from his ability to create a 
permanent supply of beef and mutton, by taming wild sheep and 
oxen, he began to experiment with all kinds of wild species; 
either because they promised to furnish him with the necessaries 
of life, or pleasure in the contemplation of beasts and birds kept 
as “pets.” He probably experimented with both hares and 
rabbits, and found the latter were readily amenable to domestica- 
tion, while hares were not. 

There is no evidence to show that the domestication of the 
rabbit is of any very great antiquity. Yet some very remarkable 
breeds have been produced, such, indeed, as could never contrive 
to exist in a wild state, as for example the “lop-eared” rabbit. 
_ This, in bodily size, far exceeds the ancestral wild rabbit, from 
which it further differs in the enormous:size of its ears, which may 
measure as much as 28 inches long and 6 inches wide! No wild 
rabbit could exist whose ears trailed along the ground with its 
every movement. ‘The long, woolly-haired Angora is another 
striking transformation of the original wild rabbit, while in point 
of size the “Flemish giant” is equally remarkable—a full-grown 
buck sometimes weighing over fourteen pounds! 


§ 8 


Elephants, Camels, and Llamas 


The domestication of the elephant, camel, and Ilama sup- 
port the view already put forward here, that man’s choice of 
domesticated animals has in no small degree been determined by 
force of circumstances. That is to say he brought into subjec- 
tion the most adaptable of the wild animals nearest to his hand. 

The Indian elephant alone, of the two existing species, has 


The Story of Domesticated Animals 1127 


proved amenable to domestication. Even this but seldom breeds 
in captivity, so that the stock has continually to be replenished 
by wild-caught animals, which present a most surprising amena- 
bility to captivity. 

Of the two species of camel, one, the Arabian camel, has so 
long been extinct as a wild animal that we are unable to say with 
certainty whence the first of the domesticated stock was derived. 
Of the Bactrian or two-humped species it is said that a few wild 
animals are still to be found in the remote parts of Turkestan. 
Both species not only breed readily but they can be freely 
crossed. Among the Yourouks of Asia Minor the resultant hy- 
brids, or “mules,” are preferred to either of the pure breeds. 

The western side and the southernmost parts of South 
America harbour some near relations of the camels of the Old 
World—the llama and the alpaca. ‘These are domesticated 
breeds of wild species. Up to the time of the Spanish Conquest 
the Peruvians possessed neither horses, cattle, nor sheep. They 
were dependent on the llama alone for meat, milk, and clothing, 
and for beasts of burden, and this beast still continues to fulfil 
these several needs of their owners, even though domesticated 
animals, horses, cattle, and sheep, have been introduced from 
Europe. The alpaca is of little use as a transport animal, but 
it provides a most valuable “wool” for clothing. 


§ 9 

The Taming of the Birds 

Turning now from mammals to birds we find that here also 
man has made some signal conquests, though it would seem that 
he did not try his hand at the subjection of the Fowls of the Air 
until he had evolved a comparatively stable mode of life. Migra- 
tion, accompanied by flocks and herds, was not only easy but 
necessary. During these peregrinations, however, it would be 
impossible to transport feathered live-stock. 


1128 The Outline of Science 


Probably the earliest of his experiments was made upon 
ducks and geese. The mallard then, as now, proved readily 
amenable to domestication, as also did the grey-lag goose. Of 
the two, however, the mallard has proved the more plastic. This 
is shown by the fact that it has given rise to a greater variety of 
“breeds,” exhibiting a wider diversity of structure, size, and 
coloration than is the case with the goose. 

The pigeon was a still later conquest. Our domesticated 
pigeons have all been derived from the rockdove, which, in the 
hands of the “fancier,” has undergone some really extraordinary 
transformations, as may be seen on reference to the colour-plate 
facing page 1124. 

Our domesticated ‘““Game-birds” are represented by the com- 
mon fowl, the guinea-fowl, the turkey, and the peacock. As with 
the pigeon, these are all relatively recent additions to man’s 
possessions. 

The common fowl] is a descendant of the Indian jungle-fowl, 
Gallus bankiva. Like the blue-rock pigeon this bird has proved 
to be singularly prone to variation. The number of known breeds, 
past and present, is positively bewildering: almost every con- 
ceivable change in the matter of coloration and feathering has 
taken place, while the soft parts, represented by the comb and 
wattles, have in like manner assumed strange developments. To- 
day the trend of the breeder is to produce severely utilitarian 
breeds. His aim is to secure birds with prodigious egg-laying 
powers, or birds for the table. But there is one fact which has 
escaped him: his “table-birds” are growing steadily less and less 
weighty in regard to just that portion of their anatomy which it 
is most to be desired should on the contrary increase, to wit, the 
breast muscles. These are the muscles which sustain flight, and as 
for generations untold these muscles have ceased to be used, they 
are in consequence rapidly declining. No amount of “selection” 
can remedy this. The only possible hope of stemming this decline 
is to devise some means of making these birds use their wings. 


The Story of Domesticated Animals . 1129 


It would be beyond the scope of these pages to pass in review 
the well-nigh innumerable species of birds which man has suc- 
ceeded in domesticating more or less completely, for xsthetic rea- 
sons, as “cage” birds. But we may cite the Canary as an example, 
for this bird has now become so transformed that only an ornitho- 
logical expert could identify it with its wild ancestor. Even its 


shape, in some breeds, has been changed. 


BIBLIOGRAPHY 


Darwin, Animals and Plants under Domestication. 

Lane, Rabbits, Cats, and Cavies. 

Ler, Modern Dogs. 

Low, Domesticated Animals. 

Lypekker, The Ox and its Kindred; The Sheep and its Cousins; The Horse 
and its Relatives. 

TrEGETMEIER, Pigeons. 


Wrient, Illustrated Book of Poultry. 


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XXXVIT 


THE SCIENCE OF HEALTH 


1131 


THE SCIENCE OF HEALTH 


What is Health? 

EK ALTH is a word which means so much and means so 
many things that it is impossible to compress its wide 
and varied significance within the compass of any brief 

definition. It is an ancient word, too, and it has been changing 
and widening in its connotation ever since it was conceived and 
born, and it is changing and widening still. As its derivation 
suggests, it originally meant something like wholeness, and prob- 
ably referred to freedom from obvious bodily wounds and injuries, 
and had little or no reference to the deeper and obscurer vital 
processes. It is true that Hippocrates, the “Father of Medicine,” 
defined health physiologically as a condition in which “each 
humour is in due proportion of quantity and force, but especially 
properly commingled”; but physiology was very crude and em- 
pirical in those days, and Hippocrates did not know the differ- 
ence between a vein and an artery, and could not distinguish 
between a nerve and a tendon, while Aristotle taught that the 
brain was a sponge to keep the blood cool, which is good metaphor 
but bad physiology. The work of Galen made it possible to have 
a clearer view of the physiology of health, and to-day, when 
physiology has become a great science, some very definite physi- 
ological ideas dominate the meaning of the term health, as used 
by doctors and scientific men. The body is now regarded as a 
chemical and physical system, and by health we mean mainly 


useful, efficient, and harmonious production of energy—a matter 
1133 


1134 . The Outline of Science 


depending more upon general functional harmony and perfection 
than upon anatomical integrity. 


Health as Working Capacity 


The conception of health as working capacity, founded on 
chemical and physiological bases, becomes ever more definite and 
precise with the advance of chemistry and physiology and their 
sister sciences, for we find out more and more the factors which 
affect energy income and output. To-day we may put a little 
thermometer under a man’s tongue, and if it read 102° F’. we can 
say with certitude that the man is out of health, and that he is as 
incapable of full work as an overheated engine. Or we may listen 
to a man’s heart and find that its valves leak, and we may justly 
conclude that it is as inefficient for work as a leaking pump. Or 
we may test a drop of a man’s blood and decide that the man is in 
bad health, since he lacks oxygen to keep his furnaces going full 
blast. Or we may find a microbe in a man’s veins and know that 
his energy must quickly fail. Or we may count a man’s pulse and 
find it 140, and judge at once that he is out of health and unfit for 
work. On the other hand, we may find that a man’s temperature 
is 98.4° F., that his heart is as sound as a bell, that his blood is 
pure, that he has no microbes-in his veins, and that his pulse is 72 
and of good quality, and even if the man have lost an arm or a 
leg or an eye, we can label him healthy, and can safely infer that 
he has normal health, i.e. normal capacity for work. In fact, all 
our accumulating knowledge of physiological processes makes for 
precision in our conception and measurement of health. 


The Energy of Food 


Regarded as a material system for the development and 
regulation of energy, a living animal organism is in many ways 
a mechanical marvel. Like other machines it requires fuel, and 
as in the case of other machines, its fuel is mostly carbon; but the 
carbon of food, not the carbon of coal or of oil. Now the carbon 


Required by all the tissues. (A 
daily supply is necessary to make 
good what is given off from the 
skin, lungs, kidneys, etc.) 


Enter into the composition of all 
the tissues and essential for their 
healthy activity. | 


MINERAL SALTS . 


pair wastage or to provide for immediate require- 
growth. ments may be stored, 
(2) Undergo combustion to yield for future use as a 
energy and heat. - source of energy and 
: heat, after conver- 
FATS... ee combustion to _ yield sion into adipose 


|PROTEIDS. . 


Tissue building, either to re- Part of any excess over 


energy and heat. | tissue or (except in 

the case of fats) 

Undergo combustion to _ yield into glycogen (liver 
energy and heat. starch). 


CARBO -HYDRATES 


(Sugars, 
Starches, etc.) 


a Sere as FOOD {venta insignificant, but 


(“Vitamins”) essential for good health, 


THE USE OF THE FOOD-STUFFS IN THE BODY 


Food is a source of material for tissue-building and tissue-repair, and a source of energy and heat for the activities of the body. 
The diagram shows the uses of the various food-stuffs in the body. 


Photo: Palmer Clarke. 
PROFESSOR F. GOWLAND HOPKINS, F.R.S. 


Professor of Biochemistry in the University of Cambridge 
anda great authority in this new branch of science, from 
which great advances in biology and in medicine may be 
confidently expected. He has been a pioneer in the study 


of accessory food factors or ‘‘vitamins’’ and of the part they 
play in nutrition. 


PROFESSOR J. ARTHUR THOMSON, M.A., LL.D 


Regius Professor of Natural History in the University of 
Aberdeen. Editor of ‘‘ The Outline of Science.’’ 


The Science of Health 1135 


of food is the very same carbon which the red rays of the sun tear 
from the carbon dioxide of the atmosphere in the laboratory of 
the green-leaf (see Borany, page 604). ‘The wrench of the sun 
sets the carbon vibrating with new energy, and when it is after- 
wards built into starch the energy is latent there, and is delivered 
to the animal which eats the starch (or fat or sugar or protein 
constructed out of the starch), and is manifested as actual animal 
energy as soon as the food is oxidised in the animal’s tissues, just 
as coal gives off its energy (as heat) when it is oxidised in a fur- 
nace. (When another element combines with oxygen, as carbon 
in particular so readily does, we speak of it as being owidised: the 
process is one of combustion, in which heat and energy are liber- 
ated.) If we put glowing carbon into a jar of oxygen it oxidises 
quickly and burns fiercely, while, if we put the carbon of our | 
food in contact with the oxygen carried by our red blood cor- 
puscles, it oxidises slowly and burns quietly, heating the body 
usually only to 98.4° F'., and manifesting itself not only in heat 
but in chemical, mechanical, and electrical energy. But in each 
ease the process is essentially a freeing of solar energy previously 
imparted to the carbon. Our bodies, therefore, are sun machines, 
worked by the red rays of a star 93 million miles away, radiated 
it may be a million years ago. When Gimbernat, for instance, 
consumed soup made of a mastodon’s teeth, he put into his heart- 
beat the carbon of the food crushed by the monster’s molars hund- 
reds of thousands of years ago, and the carbon had probably 
been energised in some tree-fern by the tropical sunlight of that 
prehistoric era. Gimbernat really drank in his soup not only 
gelatin from monstrous molars, but also starch from prehistoric 
trees and the red light of a prehistoric sun. We are not all so 
prehistoric in our meals as that, but every man lives and moves 
by virtue of the red light of the sun which he consumes with his 
porridge, or potatoes, or beefsteak, or bread and butter. We 
cannot wink an eyelid without liberating the energy of these red 
rays from our culinary carbon. 


1136 The Outline of Science 


Chemically speaking, foods are divisible into: carbohydrates, 
such as starch and sugar; fats, such as butter; and proteins, such 
as white of egg and meat. All such foods can be oxidised by 
burning, and their value as energy-producers can be estimated by 
the heat they give off during their combustion. We estimate 
heat in calories, a calorie being the amount of heat required to 
raise one gramme of water 1° C.; and we find on burning these 
three kinds of food in oxygen that one gramme of carbohydrate 
produces 4.1 calories of heat, one gramme of fat 9.3 calories, and 
one gramme of protein 4.1 calories. Heat is, of course, a form 
of energy, and is changeable into definite amounts of other forms 
of energy, such as muscular motion, and it is known that a calorie 
of heat is equivalent to the energy required to raise a weight of 
425.5 grammes one metre. ‘Thus it is quite easy to calculate how 
much heat and muscular energy should be given to the body by 
the slow oxidation in its tissues of certain amounts of food; and if 
we put a man in a special chamber called a calorimeter, where the 
amount of heat and of other forms of energy he expends can be 
measured, it will be found that he produces about as many calories 
of heat, and other forms of energy, as his food would produce if 
burned outside the body. Accordingly, if we know how much 
energy a man expends under various conditions, it is not difficult 
to calculate the food he requires: all living involves expenditure of 
energy, breathing and thinking as well as manual work or physical 
exercise. It is also easy enough from figures of food consumption 
to find out how many calories are contained in an average man’s 
diet. Before the war the average Englishman consumed 3,422 
calories of energy in his food; during the war, the Royal Society 
Food Committee came to the conclusion that the average man 
required 3,390 calories of energy, so that the average man would 
seem to have adapted his diet to his requirements very success- 
fully. ‘To keep the heart beating and the other organs working, 
and to maintain the temperature of the body, about 2,836 calories 
are required on the average, and any calories in excess of these 


The Science of Health 1137 


requirements are available for muscular energy. Only about 20 
per cent., however, of the calories available can be converted into 
actual muscular work; the rest is dissipated as heat. ‘Twenty per 
cent. seems a small proportion of work; but it is a larger pro- 
portion than can be obtained from any steam-engine. 


Proportions of Different Kinds of Food 

In view of these facts it might seem that a man has only to 
swallow so many calories of energy in his food in order to get so 
many calories of work from his muscles; and we find men who are 
foolish enough to eat huge quantities of food in order to gain 
strength. But food must be carefully chosen; it must also be 
suited in quantity to the “boiler capacity” of the man and to his 
digestive, respiratory, and circulatory potentialities. We must 
not take foods indiscriminately; we must take certain propor- 
tions of carbohydrates, of fats, and of proteins, and the last is 
particularly necessary, providing not only fuel to work the body 
but also material to build it up and to repair its waste, for it must 
be noticed that the body-machine not only does work but also 
builds up and repairs itself. We must also take such forms of 
these food materials as the digestive organs can digest, and we 
must consider their digestive capacity. Further, we must con- 
sider the oxidising capacity of the blood, heart, and respiration, 
for the carbon of the food is of no value for work unless there be 
oxygen to burn it. A man who is to obtain much energy from 
large quantities of food must have all his organs strong and 
efficient, otherwise the food will be wasted. A man of powerful 
constitution may be able to digest and utilise perhaps 10,000 
calories in twenty-four hours; but all men are not made that way, 
and it is perhaps just as well they are not. 

It is not necessary for a man to weigh out so many calories 
of food, and indeed it is always better for a man to weigh him- 
self than to weigh his food. If he find his weight becoming 
unduly great, that is proof positive that he is eating more than 


VOL. 1V—18 


1138 The Outline of Science 


he can turn or is turning into energy; while if he find he is losing 
weight and if there is no disease to account for the loss, that is 
proof presumptive that he is consuming his own tissues in the 
production of energy and could therefore utilise more food for 
the purpose if it were given him. Further, an observant man 
will soon discover, with a few scientific principles to guide him, 
what foods and what quantity of food result in the best output 
of energy. The trouble, of course, is that men are often care- 
less or unobservant or self-indulgent. A very busy man neglects 
his dietary till suddenly he finds his bones sticking through his 
skin and his energy unequal to his daily work. 


Sr 


The three classes of foods, as we have said, are carbohydrates, 
fats, and proteins. ‘These are the foods proper, that is to say, 
the substances whose oxidation gives man his supply of energy; 
but besides these foodstuffs proper, man must add to his dietary 
certain other substances which are necessary for the complete 
digestion, assimilation, and utilisation of these main articles of 
diet. He must include in his menu a certain amount of the 
remarkable liquid—water; he must also make sure that his 
dietary contains certain salts such as common salt, and certain 
mysterious substances called “vitamins.” But in ordinary diet- 
aries there is always water added in some form or other, and in 
any properly varied dietary, containing milk, meat, bread, and 
vegetables, there are plenty of vitamins. 


Importance of Vitamins 


The “vitamins,” or “accessory food factors,” have intro- 
duced a new idea into the theory of dietetics which is independent 
of any question of calories. ‘These substances are present in 
food-stuffs in such small amounts as to be valueless in themselves 
as sources of energy, but in some way not yet understood, they 


| BPERF BILE, 
VELL. FRI TEM ED 


BEEF ROUNCS, 
RATHER LEAN 


[MUTTON S!DE, 
WELL FATTEN EOS & 


MACKEREL, 
AVERAGE 


SALMON 


4 cow's MILK 
COW'S MILK, 


SKIMMED 


& CHEESE, 
WHOLE MILK 


BUTTER 


CIELOMARIAR EE 


WHEAT SREAG 


TT SACI IE IG 


GCATMEAL 


corte aize), 
ME AL. 


SSTATOES 


FURMI PS 


CASS MOLES 


LSAT LLL EE RTE TRENT TMT 


PPO PLES 


BANE A SS 


EXPLAMAT 1 Ohs | 


MINERAL 
SAITS . WATER 


THE COMPOSITION OF CERTAIN COMMON FOODS 


This diagram will enable the reader to see at a glance what kinds of food are especially rich in proteids, in fats,and in carbohy- 
drates respectively, and also which contain a large proportion of water and which are of a more solid nature, and how much mineral 
matter is present. Each band represents a hundred parts by weight of a particular food-stuff, and the percentages of the different 
ingredients may be read off from the scale which is marked along the top; a key to the colours is given at the bottom. A comparison 
with the diagram facing p. 1134, showing the uses to which these food ingredients are put in the body, will indicate what foods (i.e. 
those rich in proteids) are necessary for the building and repair of tissues, and which (i.e. those rich in fats or carbohydrates) are 
mainly useful as sources of body-heat and muscular energy. (Reference is also made in the text to the importance of accessory food 
factors or ‘‘vitamins,’’ but these do not occur in measurable quantities.) 


i i NPN NE AL A RS LIEU Nee oe ee 


The Science of Health 1139 


are essential to the health, growth, and even life of the body. 
They have not been isolated or chemically defined, but it is 
now becoming well-known what food-stuffs contain them, and 
what diets produce the disastrous results which mark their 
absence. They are all ultimately products of the plant world. 
Lack of one of these accessory food factors causes scurvy, a 
disease which was commoner in the days of sailing ships and of 
consequent long periods without fresh food. Lack of another 
causes the nervous disease known as beri-beri, which has a curious 
history. Some native races of India live largely on rice, and 
when machine-rolling began to replace more primitive methods 
beri-beri became rampant. It was then found that the machines 
husked the rice grains too efficiently, and that it was the lack 
of some ingredient in the husks—formerly eaten in large part— 
that caused the disease. Careful experiments in the feeding of 
pigeons confirmed the result, and when the knowledge was 
gained the remedy was simple. The third accessory food factor 
is an ingredient of animal fats, notably of cod-liver oil, and seems 
to play an important part in the physiology of growth and in 
the prevention of rickets. All these substances, as has been said, 
exist in sufficient quantity in a well-varied dietary, but wherever 
we get restriction in the nature of the diet—however ample the 
mere quantity of food—there is a danger of one or other being 
present in insufficient degree. During the siege of Kut there 
was scurvy among the British troops and beri-beri among the 
Indians, and even at home the question was an important one to 
those responsible for controlling and rationing the nation’s food- 
supply. In the feeding of infants and invalids, in the rationing 
of exploring expeditions and of military forces on active service, 
and in the food-supplies of the poor, special attention requires 
to be paid to providing adequate vitamins: without these, no 
mere sufficiency of quantity, no mere numbers of calories, no 
mere increase of proteins, carbohydrates, or fats, as such, will 
be of any avail in the preservation of proper health. 


1140 The Outline of Science 


Enjoying Food 

The whole organic well-being of a man depends on his food, 
and no man can have that harmonious output of useful energy 
which we call health if he eat too much or too little food, or if 
his digestion be inefficient. Digestion, however, begins in a 
sense in the olfactory organ, and ends in that colloid solution 
which constitutes living protoplasm, and indigestion is very often 
not due to any deficiency of the digestive organs, but can be 
attacked and cured on quite other grounds. ‘To digest food 
properly we must enjoy it (and the man who does not enjoy 
his food is unlikely to enjoy anything else), and to enjoy it 
thoroughly we must smell it and taste it. The smell and taste 


> 


of food makes the “mouth water,” and that is the beginning of 
digestion; but the smell and taste, as the Russian scientist 
Pavlov showed, also cause the stomach to “water.” ‘To eat food 
in the spirit of “dust to dust I commit” is to invite indigestion 
and ill-health, and many people suffer from ill-health simply 
because they have never learned to enjoy their food. The im- 
provement in health, i.e. the increase of energy, that often follows 
more thorough mastication, is largely due to stimulation of the 
digestion through the senses of smell and taste. The digestive 
juices, stimulated by the sense of taste and smell, were called by 
Pavlov “psychic juices,” and they undoubtedly play a big part 
in preliminary digestion. Another cause of indigestion is cer- 
tainly the lack of fresh moving air in dining-rooms. Without 
fresh moving air we cannot have sufficient respiration and circu- 
lation, and without efficient respiration and circulation the 
processes of secretion and assimilation associated with digestion 
cannot function properly. 


Muscular Development may be Exaggerated 

The great majority of people have digestions quite capable 
of supplying them with all the energy they can pleasurably and 
profitably employ. ‘There is no great advantage in the posses- 


The Science of Health 1141 


sion of large muscles and great muscular energy. So far as 
energy of that kind is concerned, a flea or grasshopper or ant or 
beetle can put man to shame. Perfect health is possible with- 
out unusual muscular development, muscular strength, or mus- 
cular endurance; and the various health systems that devote 
themselves to developing and strengthening muscles are usually 
a mistake from the point of view of energy. For at best big 
muscles can manifest mighty energy only for a few years, and 
the energy they use means unnecessary work for all the vital 
organs: it is waste of the wonderful potential energy of the 
carbon compounds. In bygone times muscular energy was of 
value in the struggle for existence. The man who could draw 
a stout bow, or swing a heavy battle-axe, or even carry a big load, 
had vital advantages over the man with weaker arms and legs; 
but even then muscular strength did not count for everything, for 
man managed to extirpate many animals ten times stronger than 
himself. Now, in these days of rifles and poison-gases and ma- 
chinery, muscle plays a subordinate part in life. From the 
carbon of his food a man may obtain a few hundred calories of 
energy for his two arms; but the energy of coal now supplies 
every man with about as many arms as Briareus, and the energy 
of oil carries a man in his motor-car as far in one hour as his 
legs could carry him in ten. Muscular energy, beyond a certain 
point, is no longer “worth the candle,” and a man may be all the 
healthier, in the fullest sense of the word “healthy,” in that he 
requires and uses only a moderate amount of muscular energy. 
The chief advantage, indeed, of coal and machinery is that they 
liberate man’s energy for higher tasks than hewing wood or 
carrying water. The average man does not now require to make 
his heart and other vital organs labour on behalf of his muscles; 
he can make his muscles labour on behalf of his vital organs, 
and especially on behalf of his brains. He can take muscular 
exercises to develop his breathing capacity, to strengthen the 
grip of his heart, to improve his circulation and to stimulate his 


1142 The Outline of Science 


digestion, and all for the sake of his intellectual and esthetic 
life. Not only the idea of wholeness but also the idea of valwes 
enters into the modern conception of health, and a man who 
exercises all his energies harmoniously and in proportion to 
their spiritual and social value must be considered healthier than 
a man with the digestion of an ostrich, the strength of an ox, 


and the brains of a guinea-pig. 


Exercise 

For intellectual work little food is required over and above 
what is needed by the heart and lungs and for the maintenance 
of the body heat, and it is certain that most men, other than 
manual workers, eat more food than is necessary for the muscular 
and nervous energy they expend. It is equally certain that 
many men unnecessarily expend much more energy in muscular 
movement than is good for their mental constitution. Yet mus- 
cular exercise in moderation, after food in moderation, increases 
the sum-total of the energies. A normal man can dance, walk, 
swim, play golf or cricket, and take other forms of exercise, and 
by such exercises so increase his digestive, respiratory, and circu- 
latory powers that even after the expenditure of muscular effort 
he has more energy available than before for higher purposes. 
Exercise, short of fatigue, is one of the best ways of facilitating 
the running of all the machinery of the body, and of adding to 
the general store of energy. Some men seem to be able to main- 
tain mental energy without it, but even the strongest man will 
suffer in some degree in his mental and muscular efficiency if he 
do not exercise his muscular system, and so promote the activity 
of all his vital organs. 


Happiness Correlated with Health 

We have said that most men eat too much, or at least more 
than they require for the energy they expend; but it would be a 
mistake to carry asceticism too far. The food gives the body not 


The Science of Health 1143 


only warmth and working power, it has also some subtle action 
on the character and temperament. A hungry man is an angry 
man, a well-fed man is often a warm-hearted man, and a fat 
man a contented man. Energy—even mental energy—is not 
everything, and it is sometimes wise to sacrifice a little efficiency 
for the sake of a little happiness. It is probably better to be 
happy and unhealthy than healthy and unhappy (though the 
choice may seldom have to be made), for happiness liberates and 
directs energy even if it does not create it. On these grounds, 
and only doubtfully on these grounds, can the use of alcoholic 
drinks be justified. It is well proved now that alcohol has very 
little food value, and that even in small doses it reduces energy 
and possibly shortens life, but if it gladden a sad heart it gives 
both heart and brain more driving power and makes life more 
worth living. Food may be the best fuel for the machine, but 
where life’s wheels grate dry, happiness is a good oil. 


§ 2 

Respiration and Circulation 

So much for the relationship between food, muscular exercise, 
and general health. But as we have already indicated, food and 
muscular exercise cannot be considered apart from respiration 
and circulation. If the food keep the heart and lungs going, no 
less do the heart and lungs give the food its driving power. We 
have already explained that the main source of the energy of the 
body is the energy liberated by the carbon on oxidation. ‘The 
oxidation of the carbon is effected by the oxygen which is loosely 
combined with the colouring matter of the red blood corpuscles; 
the act of respiration brings oxygen to the blood, and removes 
from it the carbon dioxide which collects in it as a result of the 
combustion of the carbon in the tissues. Except for the oxygen 
and the oxidation, the energy ultimately traceable to the solar 
rays might remain latent in the carbon compounds for ever. 


1144 . The Outline of Science 


Who knows for how many hundred thousand years the solar 
energy had been imprisoned in the mastodon’s tooth ere Gim- 
bernat swallowed it in his soup, and oxidised it with the oxygen 
of his blood, and turned it into heat and motion? 

The regulation of both circulation and respiration is auto- 
matic. When a man does hard muscular work, his breathing 
automatically quickens and deepens in order to provide oxygen 
and remove carbon dioxide, and the heart beats stronger and 
faster to carry oxygen to the tissues and carbon dioxide from 
them. During hard exercise, ten times as much oxygen may be 
consumed and ten times as much carbon dioxide discharged as 
during rest. Plainly, then, a man’s muscular energy depends 
not only on the energy supplied to his muscles by his food but 
also on his respiratory and circulatory efficiency. A man may 
have a good digestion, but if his lungs or his heart are diseased 
or impaired in their action he will not have full energy. The 
three great systems must work in harmony, and the strongest 
member of the Triple Entente must accommodate itself to the 
capacity of the weakest. A man with a weak digestion must 
recognise the fact and must “cut his coat according to his cloth.” 
The essence of health is harmonious energy, and lack of health 
is largely disharmony. The average man does not require a 
large income and output of energy, but he requires such efficient 
and harmonious working of his vital organs as will make mental 
and physical work, within reasonable limits, not only possible 
but pleasurable; and this happy consummation is within the 
average man’s reach, if he eat, exercise, and breathe wisely. Food 
and exercise we have already discussed; let us now look for a 
moment at breathing. 


The Breath of Life 

In recent years a great deal has been written on the sub- 
ject of breathing exercises. Breathing, however, is an automatic 
action which never ceases from birth to death, an action, too, 


Photo: Bacon. 
SIR FREDERICK TREVES, BART., G.C.V.O. 


A famous exponent of the modern science of operative 
surgery. 


Photo: J. Russell & Sons. 
THE LATE SIR WILLIAM OSLER, BART. 


Until his death a few years ago he was Regius Professor of 
Medicine in the University of Oxford. He was remarkably 
successful in applying scientific methods of research to the art 


of healing. 


From Report No. 14, Industrial Fatigue Research Board. 
SCIENTIFIC MOTION STUDY—I 


This photograph, taken in the dipping department of a sweet factory, shows the oper- 
ation of covering a chocolate. The white line traces the movements of the instrument 
held by the worker. Even an experienced hand, such as the one shown, performs many 
unnecessary movements owing to want of training in systematic methods. 


“From Report No. 14, Industrial Fatigue Research Board. 
SCIENTIFIC MOTION STUDY—2 


The same operation is illustrated as in the previous photograph. The movements have 
been studied, analysed, and reduced to their simplest and least tiring form. By the 
applicationof methods of this kind toindustrial processes, output can be increased, while the 
strain in the worker is at the same time reduced. (See page 1154.) 


The Science of Health 1145 


which is regulated by a series of nervous and chemical reflexes, 
and breathing exercises for a few minutes a day will have little 
effect on the total ultimate respiratory efficiency. The best 
breathing exercises are muscular exercises in the open air. Any 
exercise whatsoever that demands oxidation for muscular work 
will, as we have said, quicken and deepen the breathing, and the 
quickening and deepening will not, as in voluntary breathing 
exercises, stand by themselves; they will be an integral part of 
a general increase in vital activity. The chief desiderata are that 
the exercises should be qualified by the efficiency of the heart 
and lungs, and that they should be taken in the open air so that 
plenty of oxygen may be ready to hand. Only in this way can 
the average activity of oxidation and the average output of vital 
energy be increased, and to the ordinary man leading a sedentary 
life it is the average output of vital energy—the average output 
of mental energy—that matters. 


The Body Temperature 


There are other things, however, even more important than 
muscular exercises for the maintenance of respiratory activity 
at a height conducive to mental and physical energy, and these 
things are temperature and skin reflexes. As we have already 
pointed out, about 80 per cent. of the energy value of food is 
manifested as heat, and the heat normally maintains the body 
at a temperature of about 98.4° F. Since, then, any increase in 
muscular energy means proportionate increase in heat produc- 
tion, there must also be increased loss of heat from the body, else 
the temperature of the body will rise. For instance, 200 calories 
of an increase in output of muscular energy will mean an increase 
of 800 calories in heat production, and if this extra heat be not 
conducted or radiated or evaporated away the temperature of 
the body will rise. Briefly, there can be no increase of muscular 
energy without quicker production and loss of heat, and if loss 
of heat do not keep pace with production of heat the temperature 


1146 The Outline of Science 


of the body Will rise, and fever with disastrous results will follow. 
Nature meets this situation by taking measures to accelerate and 
facilitate the loss of heat. The skin becomes flushed with warm 
blood, so that the heat can radiate away into the atmosphere, and 
the skin also becomes moistened with sweat, so that heat may 
be removed by evaporation. But it is plain that if the atmos- 
phere be hot and damp and still, these measures will not be 
very efficacious, since both radiation and evaporation will be 
hindered, and in such a case Nature wisely refuses to allow an 
increase in the output of energy. She takes away a man’s ap- 
petite and slows down his vital machinery. We know that in 
hot damp climates all men suffer from lack of energy, and that 
muscular work often means heat apoplexy. 


The Climate under the Clothes 

The commonest cause of ill-health, lack of appetite, lack of- 
energy, lack of spirits, general tiredness, is nothing else than a 
damp, warm, still atmosphere, sometimes outside, sometimes 
inside, somtimes both outside and inside a man’s clothes. In a 
warm, tropical climate the trouble is chiefly in the outside atmos- 
phere; but many of those who do not live in the Tropics lke 
damp, warm still air in their rooms, especially next their skin and 
under their clothes. It is the climate under the clothes that is 
of the chief importance to health, and there are thousands of 
people in England who keep under their clothes the climate of a 
tropical marsh—hot, damp, stagnant. ‘They render it impossible 
for heat to escape, and Nature has to choose between giving them 
heat apoplexy and damping their furnaces. She chooses the 
less of the two evils and damps the damp man’s furnaces, and he 
is ungrateful enough to complain of lack of appetite and lack 
of energy. 

Luckily for themselves most men live in two climates at 
once. Their bodies, arms, and legs languish in the Tropics, while 


their face, neck, wrists, hands, ankles, and sometimes feet ‘carry 


The Science of Health 1147 


on” in a temperate or cold climate. In fact, face, neck, wrists, 
hands, ankles, and feet act as radiators, and if it were not for these 
radiators most English men and women would be as limp in 
London as in Zanzibar. If a man were to wear an undervest 
and a shirt and a waistcoat and a coat and an overcoat over his 
whole body 


face, hands, and neck—his energy would quickly 
flag. It is just his radiators that save him, and the open necked 
dresses that women have recently been wearing undoubtedly in- 
crease the energy of women by increasing their radiation. But 
such radiators are not enough; if a man wishes to enjoy energetic 
health he must burn energetically, and must permit free radiation 
from his whole body. We go to the hills and the seaside, and we at 
once feel invigorated, and say that the change of air has done us 
good. But there has been no change of air; it is Just the same air 
as before, only it is air in motion with hill-breezes or sea-breezes, 
and it gets under our shirts, blows away the damp hot air there, 
and increases radiation. Without adequate radiation it is im- 
possible for either the engines of the body or the engines of a 
motor-car to work efficiently. Moving air within our walls and 
within our garments is a prime condition of good working 
capacity. 

The climate under the clothes is of importance not only from 
the point of view of loss of heat but also from the point of view 
of loss of water. Under normal conditions of heat and exercise 
the skin excretes about a pint of water every twenty-four hours, 
and during violent exercise, in great heat, quarts of water may 
be excreted. If the air under the clothes is saturated with mois- 
ture, not only is the cooling of the skin by evaporation hindered, 
with results we have already noted, but the excretion of water 
is retarded and the tissues are apt to get waterlogged. ‘There 
are millions of sweat glands, with tubing altogether twenty or 
thirty miles long, and any interference with their free secretion 
reacts injuriously on the health. We have all experienced the 
tired feeling consequent on wearing an air-tight and waterproof 


1148 The Outline of Science 


coat. A man living in a room full of warm still air is bound to 
have a damp sub-tropical climate under his waistcoat, unless he 
have actual open-window ventilation; and the ventilation of a 
room is not satisfactory unless it remove not only the vitiated 
air within the walls, but also the damp and vitiated air under the 
garments. ‘Thorough ventilation is the draught in the furnace 
of vitality. | 

In still other ways the climate under the shirt is of great 
importance in the production of energy. In nature and origin 
the skin and the brain are bound up together, and messages from 
the skin nerves play a great part in the initiation and regulation 
of impulses from the brain to the vital organs. A cold douche 
makes one gasp, a cool breeze restores a fainting man, stimula- 
tion of the skin excites breathing movements in a new-born 
infant, and messages from the skin to the brain are followed by 
messages from the brain that bring about contraction or relaxa- 
tion of the vessels of the skin to suit the temperature of the air. 
But when we surround the skin with a layer of warm, damp, 
stagnant air we shut it off from the stimulus of moving air, and 
also from the stimuli of heat and cold, and no messages go from 
the skin to the brain urging it to quicken the respiration or in- 
crease the blood-pressure. And so the nerve-centres in the brain 
that control breathing and blood-pressure become lethargic, and 
the vital functions suffer in their efficiency. A man whose whole 
skin is open to the stimulation of moving air, of heat and cold, 
and perhaps of light, will have more physical and mental energy 
than a man who protects his skin from these natural and health- 
ful stimuli. 


Open Air and Light 

The open-air treatment of tuberculosis is based on the 
physiological principles which have just been explained. The 
patients are encouraged to live night and day in moving air. 
The result is that oxidation is encouraged, and the energy of all 


The Science of Health 1149 


the vital functions increased, not only as regards such functions 
as circulation and respiration but also as regards the secretory 
and excretory functions, and the chemical processes that play a 
part in resisting microbes and their poisons. What exact part 
the sun’s rays themselves may play in the matter is uncertain, but 
recent research work suggests that it may be important, and that 
the chemical processes taking place in the blood are greatly 
affected by light. It is probable, therefore, that measures for 
abating the smoke nuisance in industrial centres are even more 
urgently required in the interests of health than had previously 
been supposed. 


§ 3 


Sleep 


There remains still to mention the most mysterious and one 
of the most important of all the factors relating to vital energy. 
A man may live for weeks or months without food; but he can- 
not live many days without sleep. Without sleep his energy 
quickly fails, however much food he may take and however much 
oxygen may be at his disposal. Why sleep should be so essential 
it is difficult to understand. Theoretically speaking, so long as 
digestion, circulation, and respiration work, energy should be 
produced indefinitely, but in some way sleep is necessary for the 
continuance of vigour, especially as regards the brain and 
nervous system. The loss or partial loss of consciousness 
characteristic of sleep is probably due to a complex of causes— 
relaxation of certain blood-vessels, accumulation of waste pro- 
ducts, some kind of fatigue blockage in the nerves of sensation 
—and during the period of sleep the vital organs work more 
feebly, and more oxygen is absorbed than expended. Sound 
deep sleep is essential if a man is to enjoy full vigour, and a 
great deal of lassitude and lack of energy is due to too late hours 
and too little sleep. Lucky men who can sleep as long as they 
wish should avail themselves of the gift, and not attempt to add 
to the length of their days by stealing a few hours from the night. 


1150 The Outline of Science 


But in many cases short hours of sleep are quite compatible with 
sound health. Brain-workers, especially, seem able to maintain 
mental energy without many hours of sleep, and indeed, sleep 
requirements seem to vary to a large extent in various indi- 
viduals. When actual insomnia occurs, physical and mental 
energy diminish; and every effort should be made to get at 
the cause underlying the condition, for insomnia is not so much 
a disease as a symptom. ‘The cause may be indigestion, fever, 
physical or mental fatigue, or even surplus energy. When any 
obvious causes such as these are found, the first thing to do is 
to remove them. Sleeping draughts, at all times very dangerous 
and pernicious things, are quite out of place in such cases. What 
is the use of giving an opiate to a man whose brain has been dis- 
turbed all night by messages of remonstrance from an overladen 
stomach? If insomnia be due to undigested food, the right and 
reasonable way to avoid it is by going to bed with an empty 
stomach. If, again, as is sometimes the case, the brain is kept 
awake by a stomach requesting more food, a little food will be 
better than any soporific. If a man cannot sleep because he is 
not tired enough, the obvious remedy is to give him more work 
to do; and if he cannot sleep because he is too tired, the remedy 
of less work is obvious. Excitement, often quite pleasurable 
excitement, especially excited suspense, will often cause wakeful 
nights, and the cure, of course, is to avoid excitement, so far as 
possible, especially towards bedtime. People temperamentally 
excitable are particularly liable to insomnia, and in certain cases 
the only cure is the persistent cultivation of a calmer and more 
phlegmatic character. Excitement acts to.a large extent by 
quickening the action of the heart, and thus preventing the 
reduction of the blood-flow to the brain, which is one of the 
essential preliminaries of sleep; and even apart from excitement, 
conditions of circulation sometimes cause excess of blood in the 
brain, and this can frequently be relieved by giving warm baths 
or hot drinks. 


The Science of Health 1151 


Much more troublesome, are cases of insomnia due to what 
is called “worry.” Worry is some unpleasant or irritating 
thought that possesses or obsesses the mind, very often some 
pressing problem that insists on solution. ‘To a certain extent 
worry is inevitable; life, for most people, is full of problems that 
require to be solved, and that require persistence and concentra- 
tion for their solution. In the darkness and silence of the night 
these problems intrude and start trains of thought lying ready 
in the subconscious mind, and once these are started they turn 
the brain into a weary and sleepless Sisyphus. ‘There is no 
remedy for such worry-insomnia except to keep the mind during 
the day as much as possible from worrying matters. It must 
be noticed, too, that insomnia itself is apt to become a worry. 
The sleepless man les awake worrying about his insomnia, and 
his emotional concentration on the subject renders sleev quite 
impossible. Possibly more harm is done to a man’s health by 
worry over insomnia than by insomnia itself, and if a sleepless 
man can lie quiet, keep his mind on pleasant topics, and take 
the whole matter philosophically he will suffer very much less 
from loss of sleep than if he tosses about and frets and laments. 

We have talked of worry in relation to insomnia, but quite 
apart from insomnia, too persistent preoccupation with the dark 
side of lfe—with its anxieties and sorrows and problems—re- 
duces health and energy. The energy which ought to go to the 
vital organs is in some way inhibited, and indigestion and other 
symptoms of organic disorder follow. It is a man’s duty both to 
himself and to other people to look so far as possible at the bright 
side of things, and to cultivate the power of setting worries aside 
and of rising superior to at least the petty annoyances of daily 
life. To a great extent, avoidance of worry is a matter of the 
education of the will; but it is certain that a man living a healthy 
open-air life is more able to throw off cares and troubles than a 
man whose vitality has been reduced by unhealthy habits. Not 
only worry, in the usual sense of the term, but all unpleasant 


1152 The Outline of Science 


emotions have a pernicious effect on the health. Fear, hatred, 
envy, disappointment, all depress and disturb the vital functions. 
A man suffering from a grievous disappointment loses his appe- 
tite: and in India a man suspected of theft is given rice to chew, 
since if he be guilty fear will dry up his mouth and render him 
unable to swallow the dry rice. 

And if it be true that worry and unpleasant emotions depress 
vitality, it is equally true that joyful emotions have the opposite 
effect. 


A merry heart goes all the day, 
Your sad tires in a mile-a, 


is sound physiology, and equally sound physiology is expressed 
in the proverb “He that is of a merry heart hath a continual 
feast.” It is not enough to resist depressing emotions: a man 
who is to make the most of himself must seek happy experiences. 


Health is necessary for happiness, but also happiness increases 
health.* 


§ 4 


We have stated that great energy alone does not constitute 
health, that the energy must be harmoniously co-ordinated to 
useful and, so far as possible, intellectual and spiritual ends. 
But the useful co-ordination of energy is the function of the 
nervous system, and in a sense the nervous system is the real 
man. ‘There is a preparation in the Royal College of Surgeons 
which shows the whole nervous system of a man dissected out 
from his body, and if there were some way of supplying such a 
nervous system with food and oxygen we would have a conscious 
being that might be called a man; but take away the nervous 
system and the other organs and tissues would never be anything 
like a man. Thought, sensation, and the regulation and co- 
ordination of the muscular movements, voluntary or involuntary, 

See “The Cult of Joy, p. 359. 


Photograph: J. B. Cohen, F.R.S. From Special Report No. 52, Medical 
Research Council. 


PHOTOGRAPH OF A LEAF FROM A CITY TREE (LEEDS) 


The photograph illustrates the extent of air-contamination by city 
smoke. The soot has been removed from half the leaf for purposes of 
comparison. 


be ‘ 
Microphotograph: after Watt, Irvine, and others, ‘‘ Silicosis,” 
Pretoria, 1916. 


PHAGOCYTES OR WHITE BLOOD CELLS DEFEND THE 
BODY FROM INVADING MICROBES 


The illustration shows phagocytes in the alveoli of the lung 
loaded with coal-dust. They are ingesting the foreign particles. 


Photo: Russell, LonZon. 


SIR ALMROTH WRIGHT 


An authority on questions of immunity and a pioneer in 
modern methods of treatment by vaccine therapy. His name is 
especially associated with the substances formed in the blood 


which were named by him ‘‘opsonins,’’ and to which referenceis 
made in the text. 


Photo: Bennington. 


ALBERT EINSTEIN 


The creator of what may prove, in its implications, to be the 
most far-reaching scientific theory that the world has yet seen. 
Einstein was born in Germany in 1874. At 18 years of age he 


had already conceptions of his theory. At the age of 27 he 
published the Special Theory of Relativity. 


The Science of Health 1153 


reside in the brain, spinal cord, and nerves, including, of course, 
the wonderful nerve structures called the special senses. With- 
out this nervous hierarchy not a single useful movement could be 
performed, and life itself would be impossible, for without 
exquisitely regulated and co-ordinated action the circulation 
and breathing could not go on. This wonderful system is to a 
certain extent, as we have already suggested, under the control 
of the will, and through it a man is able to have a good deal of 
influence indirectly on other organs not under will control 
(otherwise it would not be much use to write on the science of 
health), and again through the relationship of these to the nerv- 
ous system he can influence the nervous system itself. Thus 
through the co-ordinating power of his nervous system a man 
can feed himself, feed his heart and lungs, and through them 
ean feed his brain and nerves. Accordingly, though the nervous 
system stands pre-eminent above all other systems, guiding and 
ruling them, it is dependent on the health of the other systems, 
and its health can be promoted chiefly by the measures which we 
have already mentioned when talking of the digestive, respira- 
tory, and circulatory systems. It is, however, particularly re- 
sistant to ill-health. So long as there are food and oxygen to be 
had, the nervous system will clutch them, and it is the last organ 
in the body to suffer from under-nutrition. It is essential that 
this should be so, for if the nervous system failed first, all the 
functions of the body would become chaotic and anarchical. 
When McSwiney starved himself, his mind remained active and 
clear almost to the very end. On the other hand, the nervous 
system, especially the intellectual faculties of the brain, is 
easily disordered by certain poisons circulating in the blood 
—such poisons as the toxins of fever, alcohol, opium, Indian 
hemp. 

But the chief hygienic peculiarity of the nervous system 
depends on the peculiar function of the brain as the organ of 
thought. The health of the brain as an organ of thought de- 


VOL. IV—I9 


1154 The Outline of Science 


pends not only on air and food but also on education. The brain 
feeds on books and on thoughts quite as much as on bread and 
butter. A single paragraph in a book may wind it up for days, 
and a few words on a telegraph form may unlock thousands of 
calories of energy. Its co-ordinating, its guiding, its initiative 
powers, its capacity for happiness, and its capacity for giving 
happiness can be multiplied a thousand-fold by education. 


Mental Hygiene 

There is, thus, a hygiene of the mind as well as a hygiene of 
the body. ‘To achieve the ideal of “Mens sana in corpore sano,” 
a healthy mind in a healthy body, it is necessary to apply the 
fruits of the knowledge gained not only in the realm of physi- 
ology but also in that of psychology (see THE ScIENCE OF THE 
Minp, p. 541). The mind, no less than the body, requires to be 
properly exercised and properly reposed, and it must be given 
intellectual and emotional “food” of a suitable kind. How im- 
portant this is considered may be judged from the recent forma- 
tion of a distinguished National Council of Mental Hygiene to 
promote the study of the subject and the dissemination of know- 
ledge on the questions involved. In the particular field of 
industry, also, we have the young science of “Industrial Fatigue” 
—the word is used not in its ordinary sense of “weariness,” but in 
the scientific sense of reduced efficiency. In this we find attention 
given, both from a physiological and a psychological point of view, 
to many problems of economy of effort, of monotony, of rhythm, 
of vocational selection, of spells of work and the introduction of 
rest pauses, of factory conditions, and the like: and as our know- 
ledge on these points increases, so does our capacity to improve 
the well-being and happiness of the worker on the one hand and 
our industrial output on the other. 

Nervous ill-health begins when a man’s nervous system is 
so readily and so violently excited by stimuli that the nerve- 
power is wasted and exhausted; or when a man has such deficient 


The Science of Health 1155 


nerve-power that his nerve-responses to stimuli are no longer 
easy and effective. In the first case we say the man is nervous 


x) 


or neurotic; he is always “on the jump,’ excitable, irritable, 
generally “nervy,” and periods of exhaustion alternate with 
periods of excitement. In the second case the man is nervously 
weak or neurasthenic; he is always tired, he lacks interest in life, 
and initiative, and enthusiasm; the “grasshopper is a burden,” 
and all the vital processes are depressed. Closely allied to these 
two conditions is hysteria. 

Both neurotic and neurasthenic conditions are, to a certain 
extent, innate; the nervous system, more than any other system, 
is born, not made, and some men are born with over-excitable 
nervous systems and some with too little nerve vigour; but both 
conditions can be bettered to a very great extent both by the edu- 
cation of the will and by the hygienic measures which we have al- 
ready detailed in dealing with the other systems. Under proper hy- 
gienic treatment, most neurotics can acquire steadier, more stable 
nerves, and most neurasthenics larger reserves of nerve energy. 

In talking of health, whether of body or mind, it must 
always be recognised that there is no such thing as standard 
health—no such thing as absolute health. Different men are 
healthy in different ways and to different degrees, and it is 
necessary for each man to find out his own way of health and 
acquiesce in his own limitations. A 3 h.p. engine will not lft 
an aeroplane nor drive along a liner, but it will work usefully 
and harmoniously in a motor-bicycle, and one of the commonest 
causes of breakdown in health is the employment of 3 h.p. engines 
to do 300 h.p. work, either mental or physical. The test and 
proof of health, indeed, will be found not so much in the amount 
of work done as in its smooth facile efficiency, and in the happi- 
ness and pleasure found in its performance. Man is more than 
a working machine, and his work is to be judged not merely by 
its value in calories, but also by its emotional quality, and by 
the happiness it brings both to the worker and his fellow-beings. 


1156 The Outline of Science 


§ 5 

Bacteria—the Fruitful Source of Disease 

Although we are dealing here with health of the body, and 
not with its diseases, it is perhaps not going beyond our subject 
to remark on the great advance in recent years in the Science of 
Medicine, and in our knowledge of the human body. ‘The dis- 
coveries connected with the ductless glands, and the part they 
play in the regulation of the body, have been referred to else- 
where. As explained in the article on Biology, the ductless 
glands are organs which pour their secretions directly into the 
blood. Many of these secretions, or hormones, have an extra- 
ordinary power over the growth of the body, its rate of working 
and the co-operation of its parts. Many distressing conditions 
may result from the failure of one or other of the ductless glands 
to pour its proper secretions into the blood-stream: the whole 
chemistry of the body is deranged, but the trouble may often be 
remedied, as in the case of diseased thyroid, by the administration 
of secretions prepared from the glands of animals. Bacteria 
have also been dealt with in a previous chapter. The increasing 
mastery of the microbe—that fruitful source of disease—is one 
of the triumphs of modern medical science. ‘These injurious 
microscopic organisms invade the human body, liberate poisons, 
and work incalculable havoc. By their activity they set up 
dangerous fevers, they also break down membranes and cause 
structural injuries of a serious kind. The science of bacteriology 
is young; while there remain still undiscovered many germs of 
particular diseases, hundreds of specific germs, unsuspected only 
a few years ago, have been discovered and their life-histories 
have been unveiled in the laboratory of the bacteriologist. 

There is a long list of diseases which are caused by infections 
with micro-organisms, bacteria on the one hand and protozoa, or 
single-celled animals, on the other. ‘Thus, tuberculosis, typhoid 
or enteric fever, diphtheria, tetanus or “lock-jaw,” anthrax, 


The Science of Health 1157 


cholera, bacillary dysentery, and cerebro-spinal or “spotted” 
fever are all caused by bacteria, each particular species causing 
its particular disease, while malaria, amcebic dysentery, and sleep- 
ing sickness are of protozoan origin. Other diseases remain 
which must certainly be ascribed to micro-organisms of some 
kind, but for which no cause has yet been identified with cer- 
tainty: these include scarlet fever, measles, whooping-cough, and 
influenza. Probably the organisms in these cases are even more 
minute than those hitherto observed, and evidence is accumulat- 
ing—as recently published researches show—that there are 
organisms capable of passing through the fine filters used by 
bacteriologists. 

Luckily in the body we have two great counteractives to 
these organisms of disease: in the first place there are the phago- 
cytes, wandering white cells in the blood which engulf and digest 
microbes; in the second place the body has the power of pro- 
ducing antidotes against the deadly poisons which the intruders 
liberate in their victim’s blood. In various ways it is possible to 
increase the protective efficiency of both these natural defences 
of the body. In many cases it not only happens that a cure is 
effected, but that future attacks of the same disease are rendered 
either impossible or less serious. 

A dirty pin-prick, for instance, may be the means of intro- 
ducing into the body a host of deadly micro-organisms. In the 
blood their numbers quickly multiply, until where there were 
thousands there are millions. A series of changes takes place 
in the blood and blood-vessels. Soon there is a state of warfare 
in the body; a battle between the phagocytes or white cells (the 
word phagocyte means “eating cell’’) and the invading germs 
takes place. 


The white blood-cells squeeze through the vessel walls, and, 
in their thousands and millions, gather round the point of 
disturbance. Rapidly the jelly-like cell alters its shape, 


1158 The Outline of Science 


steadily surrounds one microbe after another, until its body 
contains ten, fifty, one hundred, or more. If the conditions 
are favourable to the white cells, the battle goes on until 
every microbe is absorbed by a cell, until the exudation, solid 
or liquid, is all reabsorbed, and until the circulation of the 
blood in the part again becomes normal. 


The issue, however, may be very different. ‘The numbers of the 
invading germs may be too great; 


then millions of white cells die in the struggle, their bodies 
perhaps breaking up and lberating small quantities of anti- 
toxin. ‘The micrococci (minute germs) too die in their 
millions; but their rate of increase is enormous, and they 
continue to advance. ‘To meet them come millions more of 
the white cells, absorbing their enemies, digesting them, 
and producing the antidote to the poison of the microbes. 


If the microbes continue to gain the upper hand and invade the 
larger vessels of the body, the battle continues there; 


if the microbe meets its antidote everywhere its warfare fails. 
If, however, the conditions are still unfavourable to the 
white cells the microbes, dying in millions, produce more 
millions to continue the invasion. The war goes on until 
every defence is broken down; then the slight inflammation 
of the pricked finger ends in a fatal blood-poisoning.* 


We have said that the body has the power of producing anti- 
substances to the poisons introduced by micro-organisms. ‘These 
substances are of various kinds: they include antitoxins, which 
are antidotes to the poisons of the disease; lysins and agglutinins, 
which help directly to destroy the invading germs; and the 
opsonins (a word meaning a sauce or seasoning) discovered by 
Sir Almroth Wright. These last seem to act indirectly by aiding 
the phagocytes, apparently making it easier for these white cells 
to take in and digest the particular organisms concerned. 


1Sir Leslie Mackenzie, Health and Disease. 


The Science of Health 1159 


Artificial Immunity 

One attack of certain diseases confers a passing or perma- 
nent immunity against another attack of the same kind, but 
although this fact is ancient knowledge, its inner meaning is as 
yet by no means fully understood. But acquired immunity—the 
immunity which one attack gives against a subsequent infection 
—has suggested a line of attack on infecting micro-organisms. 
The invading organisms produce a toxin, or a mixture of several 
toxins, and in response to this the body, as we have seen, pro- 
duces an antitoxin—an antidote to the bacterial poison. But 
the process takes time, and the toxin always has a start and may 
even get control irrevocably. The question arises, therefore, as 
to whether the body cannot be made to produce its antitoxin 
beforehand: then the further question, cannot the antitoxin be 
made outside the body altogether and held in readiness to be 
injected as soon as the disease becomes manifest? 

The earliest answer to the first of these questions dates from 
long before the era of modern scientific knowledge. Artificial 
infection from mild cases of smallpox was practised in the East 
centuries ago as a protection against possible attacks of a severer 
nature, and the custom was introduced into this country early 
in the eighteenth century. It has since been superseded, how- 
ever, by Jenner’s discovery of vaccination, a safer method in 
which the artificial infection is with calf-lymph containing the 
virus of cow-pox (possibly a mild form of the same disease). 
Vaccination and improved sanitation have together banished 
smallpox from this country as a serious plague. 

The modern discovery and identification of the organisms 
that cause many diseases have led to a further modification in 
certain cases. In the protective inoculation against typhoid 
fever, for instance, it is dead bacteria—killed by heat sterilisa- 
tion—which are used. This process implies the administration 
of a definitely limited amount of toxin: the organisms, not being 
alive, cannot multiply in the body or produce further quantities 


1160 The Outline of Science 


of the poison. Anti-typhoid inoculation has proved immensely 
valuable, especially in the case of troops on active service as was 
shown in the late war, although the immunity given in this case 
disappears after a few years. 

There are, of course, obvious practical limitations to the 
protective inoculation of entire populations against numerous 
diseases, and wider possibilities are opened up by the discovery 
of means of producing antitoxins and the like outside the human 
body. It is not possible to manufacture these substances arti- 
ficially, for their subtle chemistry still eludes our researches to a 
large extent, but they can be produced in the bodies of animals. 
The principle is the same as that already described except that 
it is an animal which is inoculated with the killed bacteria or the 
toxins of the disease. Horses are commonly employed because 
of their conveniently large size: gradually increasing doses are 
given so that the animal’s health is not impaired, and when its 
blood is rich in anti-substances quantities are drawn off from 
time to time. The blood-serum is separated from the solids and 
subjected to various processes of purification and testing, and it 
is then made up for use on human patients who contract the 
disease. The diphtheria antitoxin is the best-known example 
of this kind. It is purely an antitoxin, an antidote to the poisons 
produced in the body by the bacteria, and does not kill the 
organisms themselves: these are dealt with by antiseptic treat- 
ment of the centre of infection in the throat. In the case of some 
other diseases, however, sera are used containing anti-substances 
which are effective not only against the toxins but also against 
the invading organisms. 

Without going further into the question, it will suffice to 
say that there is an ever-increasing number of diseases which are 
yielding to protective or curative measures based on the principle 
of acquired immunity. One important point, however, must be 
made clear. Immunity is not general against all or a number of 
diseases, but is quite specific. Immunity against one disease does 


The Science of Health 1161 


not involve immunity against others: each must be dealt with 
separately and each presents to science its own peculiar 
difficulties. 


BIBLIOGRAPHY 


Bayuiss, W. M., and others, Life and its Maintenance (1919). 

Councitman, W. T., Disease and its Causes (1913). 

Foster AND SHORE, Physiology for Beginners. 

Harvarp Heattu Tatks, e.g.: 
Brackett, C. A., The Care of the Teeth. 
Cuapin, C. V., How to Avoid Infection (1917). 
Stites, P. G., dn Adequate Diet. 
Wuire, C. J., The Care of the Skin. 

Hitt, Leonarp, The Science of Ventilation and Open-air Treatment, Parts I 
(1919) and II (1920). 

Keir, Sir Artuur, The Engines of the Human Body (1920). 

Macriz, Ronatp CampBELL, How to Keep Well, Air and Health, and Romance 
of Medicine. 

Mackenzir, Sir Lesiiz, Health and Disease (Home University Library). 

Marcu, Norau H., Towards Racial Health (1915). 

Mercunikorr, E., The Nature of Man (1903), The Prolongation of Life 
(1910), and The New Hygiene. 

Parker, G. H., Biology and Social Problems (1914). 

PorEeNoE, P., and Jounson, R. H., Applied Eugenics (1920). 

Tuomson, J. ArtHur, The Control of Life (1921). 


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SCIENCE AND MODERN THOUGHT 


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SCIENCE AND MODERN THOUGHT 


By THE EDIToR 


T is not easy to define Science. It is a system of knowledge 
built up on a basis of observation and experiment, and 
compacted by reflection on the data thus supplied. Scien- 

tific knowledge is typically of such a kind that it can be verified 
by competent inquirers who repeat the observations and experi- 
ments, and make them the subject of careful independent 
reflection. Science is verifiable, communicable, impersonal, un- 
emotional knowledge; but all the fields of science are not on the 
same level. Thus Newton’s Principia may be called very perfect 
science, but its range of communicability is limited. It is prob- 
ably easier to be impersonal in Astronomy than in Ethnology. 


The Aim of Science 


The establishment of a science depends on processes of 
selection and detachment, what might be called isolating certain 
aspects of things. Thus the geologist does not as such concern 
himself with the beauty of the scenery, nor the astronomer with 
the majesty of the star-strewn sky. Nor does the physiologist 
primarily concern himself with the subjective aspect of life, 
though here the abstraction of metabolism from mind is less easy. 
The aim of science is to work out descriptive formulz—as short, 
as simple, as complete, and as consistent as can be devised. As 
Aristotle said: “Art”? (we should say “Science”) “begins when, 
from a great number of experiences, one general conception is 


formed which will embrace all similar cases.’ Science means 
1165 


1166 The Outline of Science 


unifying diversities and detecting uniformities. As Professor 
J.H. Poynting put it: In science “we explain an event not when 
we know ‘why’ it happened, but when we know ‘how’ it is like 
something else happening elsewhere—when in fact we can in- 
clude it as a case described by some law already set forth.” As 
Professor Karl Pearson has said: 


The law of gravitation is a brief description of how every 
particle of matter in the universe is altering its motion with 
reference to every other particle. It does not tell us why 
particles thus move; it does not tell us why the earth de- 
scribes a certain curve round the sun. It simply resumes, in 
a few brief words, the relationships observed between a vast 
range of phenomena. It economises thought by stating in 
conceptual shorthand that routine of our perceptions which 
forms for us the universe of gravitating matter. 


This view of science as essentially descriptive is well suggested 
by Kirchhoff’s famous statement of the aim of mechanics—“‘to de- 
scribe completely and in the simplest manner the motions that 
occur in nature.’ Many of the misunderstandings that have 


99 66 


arisen in regard to “science and religion,” “science and philoso- 
phy,” and similar questions are due to a failure to recognise what 
Science aims at—the formulation of things as they are and as 
they have come to be. The primary aim of science is not to 


> 


“explain,” except in the sense of saying “This is a particular 
case of Law X,” or of saying, “This is the outcome of that.” It 
does not inquire into the “why” of things, the purpose or signifi- 


eance of the cosmos. That is not its métier. 


The Scientific Mood 


The scientific study of a subject implies a certain intellectual 
attitude or mood, which need not, however, be regarded as the 
only right of way. Thus the esthetic or poetic or purely practical 
approach to a subject may be not less legitimate than that of the 
scientific investigator. The scientific mood, which reaches very 
diverse degrees of development, is marked by (1) a passion for 


Science and Modern Thought 1167 


facts (this includes a high standard of accuracy and a detach- 
ment from personal wishes); (2) a cautious thoroughness in 
coming to a conclusion (this implies a persistent scepticism and 
self-elimination in Judgment) ; (3) a quality of clearness (which 
includes a dislike of obscurities, ambiguities, and loose ends) ; and 
(4) a less readily definable sense of the inter-relations of things, 
an insight which discerns that apparently isolated phenomena 
are integral parts of a system. When a body of knowledge is 
very young or very elusive, there is apt to be a penumbra of what 
Faraday called “doubtful knowledge.” One must steer between 
uncritical easygoingness and expurgatorial intolerance. 


The Methods of Science 


In any scientific inquiry the first step is to get at the facts, 
and this requires precision, patience, impartiality, watchfulness 
against the illusions of the senses and the mind, and carefulness 
to keep inferences from mingling with observations. ‘The second 
step is accurate registration of the data. In most cases science 
begins with measurement. As Lord Kelvin said, “Nearly all the 
grandest discoveries of science have been but the rewards of 
accurate measurement and patient, long-continued labour in the 
minute sifting of numerical results.”’ There is a certain quality 
of character here, and it is very significant that Clerk Maxwell 
should have spoken in one sentence of “those aspirations after 
accuracy of measurement, and justice in action, which we reckon 
among our noblest attributes as men.” 

A third step is arranging the data in workable form—a 
simple illustration being a plotted-out curve which shows at a 
glance the general outcome of a multitude of measurements, 
e.g. the range of variability in a particular specific character in 
a plant or animal. The data may have to be expressed in their 
simplest terms, reduced perhaps to a common denominator with 
other sets of facts with which they have to be compared. There is 
the danger here of losing sight of something in the process of re- 


1168 The Outline of Science 


duction. Thus, in reducing a fact of animal behaviour to a chain 
of reflex actions we may be losing sight of “mind”; or in reducing 
a physiological fact to a series of chemical and physical facts 
we may be losing sight of “life.” 

The fourth step is when a whole series of occurrences is 
seen to have a uniformity, which is called their law. A formula 
is found that fits—the finding being sometimes due to a flash 
of insight and sometimes the outcome of many tentatives. New- 
ton’s “passage from a falling apple to a falling moon” was a 
stupendous leap of the scientific imagination; the modern science 
of the atom is the outcome of the testing of many approximate 
formulations. 

The Laws of Nature are man’s descriptive formule of uni- 
formities of sequence, which enable him to say, “If this, then 
that.” These laws are not all of the same rank; they differ in 
precision and comprehensiveness; the meaning of their terms 
often changes with time. Science is not only human, it is often 
anthropomorphic. It may even reflect the social outlook of the 
age. Thus in Biology, one of the less exact sciences, provisional 
concepts, such as “the struggle for existence,” are often borrowed 
from human affairs; and while illuminating suggestion often 
comes from this, there is no small risk of fallacy. Science is not 
so objective as is sometimes supposed; we can no more escape 
from anthropomorphism than from our shadow. Yet those who 
exaggerate the subjectivity of science and declare with a great 
philosopher of to-day that “scientific truth is the creation of the 
human mind, and not of outer nature,” are missing what is 
characteristic of man’s scientific formulation of the Order of 
Nature, that it must be verifiable by all normally constituted 
minds, and that it must form a reliable basis for prediction, if 
not also for control. The fact that the astronomer can predict 
the night of the comet’s return, and the Mendelian the nature of 
the hybrid rabbit’s litter, shows that our formulations approxi- 
mate towards objective reality. 


Science and Modern Thought 1169 


Scope of Science 

There is much to be said for using the word science with a 
qualifying adjective—e.g. chemical and physical science, natural 
science, biological science, mental and moral science, social 
science, abstract science. For the various sciences differ greatly 
in their degree of precision. When we pass from chemistry and 
physics to the study of living creatures and their behaviour, to 
the study of human societies and their inter-relations, we find 
that accurate measurements and precise registration are more 
difficult, analysis is very imperfect, formulation is very pro- 
visional, test-experiments are hard to devise, and prediction is 
usually hazardous. The discovery of methods, concepts, and 
formule has advanced much further in regard to matter and 
energy than it has in dealing with the realm of organisms and 
the kingdom of man. An exact science is like a solar system, a 
young science is like a nebula, yet the student of, say, dreams 
may be as “‘scientific” as the student of rocks, provided he never 
allows assertion to outstrip evidence, and understands what he 
knows. Science includes all knowledge, communicable and 
verifiable, which is reached by methodical observation and experi- 
ment, and admits of concise, consistent, and connected formula- 
tion. But all science is not the same science. 

A saving clause of some importance relates to the use of 
scientific symbols. The modern physicist assures us of the 
reality of the atom, but until a few years ago the atom was only 
a symbol—a working hypothesis approximating to reality. 
Many terms in common scientific usage remain in the symbolic 
stage. A chromosome is a visible something, but no one has 


’ pd 


seen a “gene” or “factor.” Yet these genes are dealt with in 
modern theories of heredity as if they were seeds in a pod. ‘They 
are indispensable. No one supposes that a carbon atom has four 
hands, but this symbol has been extraordinarily useful. Fanciful 
or arbitrary symbols never live long; they are retained only when 


they afford a convenient basis for prediction and control. The 


VOL. IV-——20 


1170 The Outline of Science 


history of science shows in an eloquent way how provisional 
symbols are tested, and how some of them gradually attain to 
the dignity of realities—as the atom has done. 


Classification of the Sciences 

There are three great orders of facts: the domain of things, 
the realm of organisms, and the kingdom of man. ‘Thus some 
have spoken of the cosmosphere, the biosphere, and the socio- 
sphere. The fundamental sciences of chemistry and physics deal 
with matter and energy, especially in the physical universe. 
Biology has the life of organisms for its province. The young 
and yet, in a sense, very old science of sociology deals with 
human societies and folk-ways. Physics and chemistry are 
practically inseparable; biology and psychology often look like 
different aspects of the same elusive activity which we call life; 
sociology deals with groups of men where the whole is more than 
the sum of its parts. But there is much to be said for the recogni- 
tion of five fundamental sciences, which may be arranged on this 
scheme: 


SOCIOLOGY 


PSYCHOLOGY 


BIOLOGY 


PHYSICS 


CHEMISTRY 


It will be seen that biology occupies a central position, 
resting in part on physics and chemistry, though with independent 
methods and concepts of its own, and supplying in turn a basis 
to psychology and sociology. Each main or general science has 
its subdivisions: thus, biology includes botany and zoology; a 
great part of astronomy must be ranked under physics, and much 


Science and Modern Thought 1171 


of mineralogy under chemistry. ‘Then there are the combined 
sciences like geology and geography and anthropology, which 
use the methods and concepts of several sciences for their own 
particular purposes. Thus geography is like a circle intersecting 
four or five others for a particular end. Furthermore, there are 
“applied sciences” where departments of general science are 
focussed for practical purposes on particular sets of problems, 
e.g. those connected with the arts and crafts. Thus agricultural 
science and medical science, the science of engineering and the 
young science of education are, in great part, applied sciences, 
and are neither more nor less scientific on that account. As 
Huxley always insisted, applied science is nothing but the 
application of pure science to detailed practical problems. 

But on a different line are the abstract sciences, which deal 
with necessary relations between abstract ideas or propositions, 
irrespective of the actual content. They are deductive rather 
than inductive; ideal, not experimental; dealing with methods, 
not with observations. 'They comprise mathematics in particular, 
also statistical methods, graphic methods, and logic. Some would 
include here that part of metaphysics which has for its business 
the criticism of categories, or a study of explanations as such. 


So we reach an outline map of scientific knowledge: 


Some Special | 


Some Combined 
Sciences. 


Some Applied 
Sciences. i 


General Sciences. Sciences. 


Abstract Sciences. 


—_———————————————————_ _ | ——————— — — — —  s | 


SOCIOLOGY Ethnology Science of History | Economics 
METAPHYSICS oh 
PSYCHOLOGY | A#sthetics Anthropology Education 
LOGIC 
BIOLOGY Zoology History of the Medicine 
STATISTICAL Botany Biosphere 
ATIGIGS IRAE ELL Gii ptr oe ie 
po Nee PHYSICS Astronomy Geology and Engineering 
Meteorology Geography 
M r 
Mere whe CHEMISTRY Mineralogy | History of the Metallurgy 


Solar System 


Agriculture 


1172 The Outline of Science 


In considering such a map of the sciences it should be kept 
in mind that they differ not merely in their subject-matter, but in 
their aims and methods. The same subject may be tackled by 
several sciences. There is a chemistry and a physics of the 
human body as well as a biology thereof. The chick may be 
studied anatomically, physiologically, embryologically, psycho- 
logically, and even then we have not exhausted the totality of the 
chick. The sciences are parts of one endeavour to understand the 
order of nature and human life within it; they form a correlated 
body of knowledge; they work into each other’s hands, and 
succeed best when they recognise mutual rights and limitations. 
The chemistry and physics of the beanstalk are indispensable, but 
when they are added up they do not give us the biology of the 
beanstalk, still less of Jack. It is begging many questions to 
insist that there is only one science of nature, which describes all 
things and changes in terms of ideal motions, expressible in 
mathematical formule. This is trying to give a false simplicity 
to the facts. Even the omniscient chemist cannot tell how the cat 
will jump. Professor Dolbear writes: “By explanation is meant 
the presentation of the mechanical antecedents for a phenomenon 
in so complete a way that no supplementary or unknown factors 
are necessary.” But many biologists of to-day would agree that 
in dealing with distinctively vital behaviour, such as the cat’s 
jump, it is necessary to invoke other than mechanical factors, 
such as the organism’s power of enregistering and profiting by 
experience. There is a correlation, rather than a unity, of the 


sciences. 


Limitations of Science 

No one will be inclined to set limits to man’s understanding, 
but it is useful to recognise that science as we know it is subject 
to certain limitations. (1) There is a self-imposed limitation in 
the fact that science applies its methods to abstracted aspects 
of things. We cannot intellectually separate a living creature 


Science and Modern Thought 1173 


from its surroundings any more than we can separate a whirlpool 
from the river, yet for biological purposes we continually think 
the fish away from the sea and the bird from the air. In analyti- 
cal anatomy it is actually profitable to do so. Hven in more 
exact sciences this limitation operates. In dynamics we treat the 
mass of a body as if we studied the body under the influence of 
gravitation only. But in actual observations and experiments we 
can never secure the entire absence of electrical, magnetic, and 
other energies. In other words, science works with “ideal 
systems’; it aims at practically convenient representations of 
certain aspects of facts, deliberately abstracted from other 
aspects. 

(2) Science works with “counters” or concepts which are 
in various degrees far from being self-explanatory. What 
mysteries lie behind the terms “organism,” “protoplasm,” 


99 66 ba A AIG b De PEN F es 


“heredity,” “energy,” “chemical affinity,” “gravitation,” “iner- 


99 66 a 
! 


tia,’ “matter”! It is admitted that the analysis of concepts pro- 
ceeds apace and that the number of “irreducibles” grows less. 
But there are many “w’s” left. 

(3) Another limitation has to do with causal sequence. 
One billiard ball strikes another—an impelling cause; a spark 
explodes the gunpowder—a releasing cause; the relaxed spring 
turns the cylinder of the gramophone, and there is music. But 
it is only in the first case that the cause eaplains the effect; in the 
other cases the effect is more or less given in advance. In the 
great majority of cases all that science does is to say: “If this, 
then that.” Its causal explanations are usually very partial. 

(4) Another limitation concerns origins, which remain 
mysteries. The biologist begins with the first organisms, but 
whence came they? ‘The chemist begins with the elements, but 
what has been their history? There is always something before 
the beginning with which the scientific investigator starts and 
must start. So there are limitations implied in the partial view 


we have to take in prosecuting a scientific inquiry, in the radical 


1174 The Outline of Science 


mysteriousness of the counters we use, in the difficulty of giving 
complete causal explanations except in the field of mechanics, 
and likewise in the obscurity of origins. If these necessary limita- 
tions were more clearly kept in mind the aim and scope of science 
would be less frequently misunderstood. 

Moreover, besides all these limitations there are others of a 
different kind—imposed on us by the limits of our sense-organs, 
even when greatly helped by ingenious instruments, and by the 
narrow limits of exact data in regard to the past. Furthermore, 
it should be kept in mind that formule or laws which seemed for 
a time to fit well have often had to undergo readjustment with 
the increase of knowledge and the recognition of residual 
phenomena. So Kepler improves on Copernicus, and Newton 
on Kepler, and Einstein, some say, on Newton. Science may be 
compared to an asymptotic line, which is always approaching 
nearer and nearer to some curve but never reaching it except at 
infinite distance. Sometimes a single discovery may change the 
whole framework of a science. Thus Professor Soddy, speaking 
of radio-activity, says: 


It sounds incredible, but nevertheless it is true, that 
science up to the close of the nineteenth century had no 
suspicion even of the existence of the original sources of 
natural energy. . . . The vista which has been opened up 
by these new discoveries [of the radio-active properties of 
some substances] admittedly is without parallel in the whole 
history of science. 


And sometimes it is a new idea, like that of organic evolution, 
which changes the whole outlook of a science and makes the world 
new. 

Finally, according to well-warranted scientific belief there 
was once a time when all that happened upon the earth might 
have been formulated with apparent exhaustiveness in terms of 
matter and motion. But ages passed and living creatures emerged 


Science and Modern Thought 1175 


—a new synthesis, requiring new formule. Ages passed and 
intelligent creatures commanded their course; a new aspect of 
reality required a new science. Ages passed and Man emerged 
—with self-consciousness, language, reasoning capacity, and a 
social heritage. As the world grew older, the biosphere emerged 
from the cosmosphere, and out of the biosphere there emerged 
the sociosphere. As long as its subject-matter continues evolving 
in the direction of new integrations, science must also evolve. 


Science and Feeling 

Our life is like a prism: its three sides are (1) Dorne, (2) 
FEELING, and (3) KNowIna, corresponding to the old-fashioned 
Hanp, Heart, and Heap. Each is a doorway ouf—(1) to the 
world of action; (2) to the world of art, music, religious ritual, 
literature; and (3) to the world of externally registered thinking, 
from a stone circle to a nautical almanac, from a map to a 
census, from a calendar to a chemical balance. Men are happily 
of diverse moods: (1) Some have “a practical turn of mind,” 
with a pathological extreme in “matter-of-factness’” and 
“materialism,” but are essentially men of action, who make things 
hum and get things done. (2) Some are “men of feeling,” going 
out by the emotional doorway, with a pathological extreme in 
“sentimentalism,” but essentially men of artistic insight, and 
sometimes, as poets and seers, the makers and shakers of this 
world of ours. (3) Some are predominantly men of intellect, 


? 


who ‘elect to know, not do,’ who discover causes, uniformities, 
laws, and who try to think things out. The pathological extreme 
“botanises on his mother’s grave,’ as Wordsworth put it, and 
gibes at “proud philosophy,” but there is no doubt that the 
makers of new knowledge have transformed human life, giving 
it a new freedom and fulness. 

Every intellectual combatant seeks more or less resolutely 
to gain an all-round or synoptic view of his experience, and this 


is his philosophy. Our present point is that this must be for 


1176 The Outline of Science 


most men in a large degree a matter of temperament, according 
as the practical, the emotional, or the scientific mood is dominant. 
To return to the old-fashioned Hand, Heart, and Head, these 
are not only doorways out, they are portals in. For life is like 
a dome, always with its concave and convex side, sub jective as 
well as objective. Thus there is the inner world of appetencies 
and “urges,” desires and ideals, which lead externally to action; 
the world of feelings and emotions which lead to art; and the 
world of intellectual experimentation which has its external 
expression in, let us say, the archives of science. All these are 
natural and necessary expressions of the developing human spirit, 
and it is in the deepest sense unphilosophical to pit one against 
the other, or to make antitheses between the different glimpses of 
reality which are to be obtained from each of the three great 
doorways of our being. 

Truly, science as science is unemotional and impersonal, and 
its analytic, atomising, or anatomising methods are apt, in their 
matter-of-factness, to seem antagonistic to artistic unities and 
poetical interpretations. But here must be learned the lesson of 
patience and open-mindedness, and here the limitations of science 
must be borne in mind. The poetry of the man of feeling must 
not contradict the formulations of the man of science, but they 
are speaking different languages, and we may know by feeling 
some aspect of reality which eludes us in scientific analysis. Our 
delight in fine scenery is not less real than our knowledge of the 
geology. Both are pathways to reality. 

When science makes minor mysteries disappear, greater 
mysteries stand confessed. For one object of delight whose 
emotional value science has inevitably lessened—as Newton 
damaged the rainbow for Keats—science gives back double. To 
the grand primary impressions of the world power, the im- 
mensities, the pervading order, and the universal flux, with which 
the man of feeling has been nurtured from of old, modern science 


has added thrilling impressions of manifoldness, intricacy, 


Science and Modern Thought Tia? 


uniformity, inter-relatedness, and evolution. Science widens 
and clears the emotional window. There are great vistas to which 
science alone can lead, and they make for elevation of mind. 
The opposition between science and feeling 1s largely a misunder- 
standing. As one of our philosophers has remarked, science is 


in a true sense “‘one of the humanities.” 


Science and Religion 

Science seeks to discover the laws of concrete being and 
becoming and to state these in the simplest possible terms. These 
terms are either the immediate data of experience or verifiably 
derived from these. Religion, on the other hand, implies a re- 
cognition—practical, emotional, and intellectual—of a higher 
order of reality than is reached in sense-experience. It sees an 
unseen universe, which throws light on the riddles of the observed 
world. Its language is not scientific language and the two can- 
not be spoken at once. The concepts of religion are trans- 
cendental, those of science are empirical. The aim of religion is 
interpretation, not description. Religious interpretation and 
scientific description must not be inconsistent, but they are incom- 
mensurable. This is not falling back on the impossible solution 
of having idea-tight compartments; what is meant is that while 
the form of a religious idea, of Creation, let us say, must be con- 
gruent with the established scientific system, scientific description 
and religious interpretation work in two quite different “universes 
of discourse.” 


Science and Philosophy 

The philosophical outlook is synoptic; an all-round view. 
In other words, a philosophical system is the outcome of inter- 
pretative reflection on the whole data of our experience. Science 
and philosophy are complementary. To the scientific thinker 
philosophy is of service in helping him to recognise the limita- 
tions of his task and the assumptions with which he starts. It 


1178 The Outline of Science 


may save him from being easygoing in the criticism of his 
categories. On the other side, a modern philosophy must take 
account of all the far-reaching results of scientific inquiry. Thus 
an adequate interpretative system must have been receptive to 
all the influences of such conclusions as the principle of the con- 
servation of energy, the doctrine of organic evolution, and the 
outstanding facts of heredity. Philosophy has of course no right 
to call the tune which it wishes science to play, but its task is to 
correlate the conclusions of science with those which may be 
reached in the course of practical, ethical, esthetic, or religious 
experience. Philosophy begins where the experimental and 
observational sciences leave off, but it does not follow that 
philosophy in its edifice must use the building-stones just as 
science hands them over. It is here that philosophical criticism 
and all-roundness must come in. Thus the results of the modern 
study of heredity need not be accepted in a form so crude that 
the inevitable outcome is fatalism; the results of modern bio- 
chemistry need not be accepted in a form so partial that they 
confine us to a mechanistic view of the living creature; the results 
of the modern study of animal behaviour need not be accepted 
in a form so one sided that it practically rules “mind” out of court. 
These are merely examples of the opportunities which philosophy 
has for a criticism of scientific categories—a task for which the 
majority of scientific investigators is poorly equipped. 

To take another illustration, the principle of the conservation 
of energy, formulated in reference to the transformations that go 
on in physical experiments, must not be allowed to foreclose 
discussion of the question whether “mind” and “body” (if these 
be recognised as admissible scientific or philosophical terms) can 
interact in a way that really counts. And the answer given to 
that question, or to some similar question more satisfactorily 
phrased, affects the general philosophical or metaphysical theory 
that one holds in regard to the world as a whole and man in 
particular. 


Science and Modern Thought 1179 


Similarly, when philosophy takes over from the biologist 
the formula of organic evolution that the present is the child 
of the past and the parent of the future, it is bound to scrutinise 
the concept of evolution and to show that it is no easy one; and 
it is bound to make very clear the difference between accepting 
the modal formula (indicative of the general mode by which the 
present biosphere has come about) and accepting any particular 
statement of the factors in the age-long process. The general 
fact of evolution stands firmer than ever; but inquiry into the 
factors is still relatively young. 


Science and Life 
The primary purpose of science is understanding, but know- 
ledge is power. As Bacon said: 


The end of our foundation [Salomon’s House] is the 
knowledge of causes and the secret motions of things; and 
the enlarging of the bounds of human empire, to the effect- 
ing of all things possible. 


The two aspects are hardly separable. All the sciences, in- 
cluding mathematics, sprang from concrete experience of prac- 
tical problems, and the most theoretical investigations have made 
the biggest differences in man’s everyday life to-day. Wireless 
telegraphy, the telephone, aeroplanes, radium, antiseptics, anti- 
toxins, spectrum analysis, and X-rays were all discovered in the 
course of abstractly scientific researches. If the utilitarian 
criterion is pressed in a short-sighted way, then, as to results, it 
defeats itself. And apart from this consideration, itself utili- 
tarian, it is profitable to return to Bacon’s distinction between 
those results of science which are of direct practical utility 


(fructifera) and those which are lght-giving (lucifera)—a 


distinction which led to the admirable deliverance: 


Just as the vision of light itself is something more ex- 
cellent and beautiful than its manifold use, so without doubt 


1180 The Outline of Science 


the contemplation of things as they are, without superstition 
or imposture, without error or confusion, is in itself a nobler 
thing than a whole harvest of inventions. 


The old discouragement expressed in the saying that 
increase of knowledge is increase of sorrow has been replaced by 
a more robust confidence in what science may achieve in the 
control of life. The modern outlook is expressed in Herbert 
Spencer’s pithy sentence: “Science is for Life, not Life for 
Science,” or in Comte’s well-known saying: “Knowledge is 
Foresight and Foresight is Power.” 

Bacon had the idea clearly in mind when he wrote in The 
Advancement of Learning: “This is that which will indeed 
dignify and exalt knowledge if contemplation and action be more 
nearly and straitly conjoined and united together than they have 
been.” And the passage ends by declaring that what is sought 
in science should be “a rich storehouse for the glory of the Creator 
and the relief of man’s estate.” But what is distinctively modern 
is the ideal of bringing the light of science to bear on man’s 
problems all along the line, on health of mind as well as of body, 
on education as well as on agriculture, on ethical development as 
well as on the more economical exploitation and usage of natural 
resources, on eugenics as well as on eutopias. Just as many ills 
that the flesh is heir to are met no longer with folded hands, but 
by confident therapeutics, so over a wide range there is a promise- 
ful application of all kinds of science to the amelioration of the 
conditions of human life. Great stores of wealth are awaiting 
the scientific “Open Sesame”; a great heightening of the 
standard of health will be attainable in a few generations if men 
of good-will take science as their torch. But wealth and health 
are the pre-conditions of true progress, which means a fuller 
embodiment of the true, the beautiful, and the good in lives 


which are increasingly a satisfaction in themselves. 


Science and Modern Thought 1181 


BIBLIOGRAPHY 


Grecory, Sir Ricuarp, Discovery, or the Spirit and Service of Science 
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fel ys a P f P. 
“dh 1% Gk ROSCA. at 


ha ot hia 
= Xs al Au 4 
; i bats CSE val | 
hy 1 


i (cat ig uae 


CLASSIFIED BIBLIOGRAPHY 


1183 


o ls 
ess Kian? 7 ely Ls 
Pia Re aa 
: Ray te ‘ aa 


athe ae 


CLASSIFIED BIBLIOGRAPHY 
ANTHROPOLOGY AND ETHNOLOGY 


Barton, G. A. 
Boas, F. 
Brunhes, J. 


Chadwick, H. M. 
Churchward, A. 
Dowd, J. 
Gobineau, J. A. 
Grant, M. 
Haddon, A. C. 
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Keane, A. H. 
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b | 


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Eddington, A. S. 


Forbes, G. 
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5) 


<7 aE, | 
Lowell, P. 


’ 


soot as 
Moulton, F. R. 
Newcomb, Simon 
sai LESS OS 
Poor, C. L. 
Wallace, A. R. 
Young, C. 


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A Sketch of Semitic Origins. Macmillan. 1902. 

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Passing of the Great Race. Scribner. 1918. 

The Races of Man and Their Distribution. Miller. 1909. 

The Material Culture and Social Institutions of the Simpler 
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The World’s Peoples. Putnam. 1908. 

Culture and Ethnology. McMurtie. 1917. 

Tribes of Northern and Central Kordofau. Putnam. 1913. 

The Races of Europe. Kegan Paul Co. 1913. 

Strange Peoples. Heath. 1901. 

Some First Steps in Human Progress, Chautaugua Soc. 1901. 


ASTRONOMY 


The Sun. Appleton. 1911. 

The Binary Stars. Univ. of Calif. 1918. 

The Destinies of the Stars. Putnam. 1917. 

A Short History of Astronomy. Murray. 1898. 

Stellar Motion. Yale Press. 1913. 

The Origin of the Earth. Univ. of Chicago. 1916. 

Stellar Movements and the Structure of the Universe. Macmillan. 
1915. 

History of Astronomy. Putnam. 1909. 

A Study of Stellar Evolution. Univ. of Chicago. 1908. 

Ten Years Work of A Mountain Observatory. Carnegie Insti- 
tution, Wash., D. C. 1915. 

The New Heavens. Scribners. 1922. 

The Evolution of Worlds. Macmillan. 1909. 

Mars and its Canals. Macmillan. 1906. 

Mars as the Abode of Life. Macmillan. 1908. 

Introduction to Astronomy. Rev. ed. Macmillan. 1916. 

The Stars. Putnam. 1901. 

Astronomy for Everybody. Doubleday Page. 1902. 

Solar System. Putnam. 1908. 

Man’s Place in the Universe. 3d ed. Doubleday Page. 1905. 

The Elements of Astronomy. Ginn & Co. 1919. 


1185 


1186 


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—_ 
. e 


a. ns 
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5 


Smith, E. F. 
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Brooks, W. K. 
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Classified Bibliography 


AVIATION 
The Curtiss Aviation Book. Stokes. 1912. 


Aircraft—Its Development in War and Peace and Commercial 
Future. Scribner. 1919. 
The Aeroplane. Stokes. 1918. 


Flying—Some Practice Experiences. Longmans. 1914. 


The New Art of Flying. Dodd Mead Co. 1911. 

Vehicles of. the Air. Reilly-Britton. 1909. 

Langley Memoir in Mechanical Flight. Smithsonian Inst. 1911. 

The Romance of Aircraft. Stokes. 1919. 

Applied Aero-dynamics. Hodder and Stoughton. 1920. 

Airplanes, Airships, Aircraft Engines. U.S. Naval Inst. 1921. 

A History of Aeronautics with a Section on Progress in Aero- 
plane Design, by Lockwood March. Colliers. 1921. 

The Triumph of the NC’s. Doubleday Page. 1920. 


Municipal Landing Fields and Air Posts. Putnam. 1920. 
Aerial Navigation. Appleton. 1911. ; 


BACTERIOLOGY 


Applied Bacteriology for Nurses. 3d ed. rev. Saunders. 1919. 

Bacteriology for Students in General and Household Science. 
Maemillan. 1921. 

Agricultural and Industrial Bacteriology. Appleton. 1921. 
Microbes and Toxins. Preface by E. Metchnikoff. Trans. from 
the French by C. Broquet and W. M. Scott. Putnam. 1921. 

Bacteria, Yeasts and Molds in the Home. Ginn. 1917. 

The Story of Germ Life. Appleton. 1915. 

Bacteria in Daily Life. Longman Green. 1903. 

Bacteriology, General, Pathological, and Intestinal. Lea & 
Febiger. 1921. ; 

Bacteria, Especially as They Are Related to the Economy of 
Nature, to Industrial Process and to the Public Health. 
Putnams. 1899. 

Dust and Its Dangers. Putnam. 1910. 

The Story of the Bacteria and Their Relations to Health and 
Disease. Putnam. 1917. 

Bacteria in Relation to Plant Diseases. Carnegie Inst. 1905. 

Bacteriology and Mycology of Foods. Wiley. 1920. 

Microscopy of Drinking Water and A Chapter in the Use of the 
Microscope. Wiley. 1914. 

Bacteria and Their Products. Scott. 1903. 


GENERAL BIOLOGY 


The Elementary Principles of General Biology. Macmillan. 1914. 

Biological Facts and the Structure of Society. Oxford Press. 
1912. 

The Foundation of Zoology. Macmillan. 1899. 

Individuality in Organisms. Univ. Chicago Press. 1915. 

Fundamentals of Plant-breeding. Appleton. 1914. 

The Elements of Animal Biology. Blakiston. 1919. 

Biology and Its Makers. Macmillan. 1917. 


Loeb, J. 
Ritter, W. E. 


Thomson, J. A. 


’ 


’ 


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’ 


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Korner, A. J. 


Kraemer, H. 
Livingston, B. E. 


Macdougal, D. T. 
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The Organism as a Whole from a Physico-Chemical View Point. 
Putnam. 1916. 

The Unity of Organism or The Organismal Conception of Life. 
Badger. 1919. 

The Control of Life. Melrose. 1921. 

The Wonders of Life. Melrose. 1915. 

The Biology of the Seasons. Holt. 1911. 


GENERAL BOTANY 


Field Book of Western Wild Flowers. Putnam. 

Forest Physiography. Wiley. 1911. 

North American Forests and Forestry. Putnam. 1899. 

Plant Life and Evolution. Holt. 1911. 

The Structure and Development of Mosses and Ferns. Mac- 
millan. 1905. 

Plants—Relation and Structure. 2 vols. Appleton. 1900. 

Landmarks of Botanical History. A Story of Certain Epochs in 
the Development of the Science of Botany. Smithsonian Inst. 
1909. 

The Wonders of Plant Life. Putnam. 1889. 

Natural History of Plants. Transl. by F. W. Oliver. 2 vols. 
Holt. 1896. 

Applied and Economic Botany. Pub. by the author, Philadelphia. 
1914. 

The Relation of Desert Plants to Soil Moisture and the Evapora- 
tion. Carnegie Inst. 1906. 

The Water-Balance of Succulent Plants. . Carnegie Inst. 1910. 

Field Book of American Wild Flowers. Putnam. 1912. 

Field Book of American Trees. 1915. 

Experiments with Plants. Macmillan. 1905. 

The Fungi Which Causes Plant Disease. Macmillan. 1913. 

The Ecological Relations of Roots. Carnegie Inst. 1919. 

An Outline of the History of Phytopathology. Saunders. 1918. 

Illustrated Flora of the U. S., Canada and British Possessions. 
3 vols, Scribner. 1913. 


CHEMISTRY 


Chemistry and Civilization. Badger. 1920. 

Some Chemical Problems of Today. Harpers. 1911. 

Catalytic Action. Chemical Cat. Co. 1922. 

The Nature of Solution. Van Nostrand. 1917. 

A new Era in Chemistry; Some of the More Important Develop- 
ments in General Chemistry during the Last Quarter of a 
Century. Van Nostrand. 1913. 

Proteins and the Theory of Colloidal Behavior. McGraw Hill. 
1922. 

The Sugars and Their Simple Derivatives. Gurney and Jackson. 
1913. 

Modern Chemistry and Its Wonders. Van Nostrand. 1915. 

A History of Chemistry from Earliest Times to the Present Day 
being also an Introduction to the Science. Trans. by G. 
McGowan. Macmillan. 1906. 

The Gases of the Atmosphere; the History and Their Discovery. 
Macmillan. 1896. 

Modern Chemistry. Dent. 1900. 

Chemistry of Familiar Things. 3d ed. Lippincott. 1920. 

Liquid Air and Liquefaction of Gases. Henley. 1920. 


1188 


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Tilden, Sir. W. 


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Ames, J. S. 
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Cox, John 
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Duncan, R. K. 


Jones, H. C. 


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> 


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Bright, C. 
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Dyer, Fou 
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Creative Chemistry. Century. 1919. 

Chemistry in America—Chapters from the History of Science in 
the United States. Appleton. 1914. 

Theories of Chemistry. Winston. 1913. 

Chemical Discovery and Inventions of the Twentieth Century. 
Dutton. 1916. 

Famous Chemists—The Men and Their Work. Rutledge. 1921. 

The Study of the Atom or the Foundation of Chemistry. Chem. 
Pub. Co, 1904. 


CONSTITUTION OF MATTER 


The Constitution of Matter. Houghton Mifflin. 1913. 

The Nature of Matter and Electricity. Wan Nostrand. 1917. 

Beyond the Atom. Putnam. 1913. 

Relativity and the Electron. Longmans, Green. 1921. 

The New Knowledge (A Popular Account of the New Physics). 
Barnes. 1905. 

Electrical Theory of Matter and Radio-activity. Van Nostrand. 
1910. 

The Electron. Univ. of Chicago. 1917. 

Theories of Energies. Putnam. 1918. 

The Electron Theory of Matter. Putnam. 1916. 

Radio-active Substances and Their Radiation. Putnam. 1918, 

Radio-active Transformation. Scribners. 1906. 

The Interpretation of Radium. Putnam. 1922. 

The Corpuscular Theory of Matter. Constable. 1907. 


ELECTRICITY 


The Electrical Transmission of Energy. Van Nostrand. 1907. 

The Age of Electricity from ambor-soul to Telephone. Scribner. 
1901. 

The Story of the Atlantic Cable. Appleton. 1903. 

The History of the Telephone. McClurg. 1910. 

The Nature of Matter and Electricity—An Outline of Modern 
Views. Van Nostrand. 1917. 

Kdison—His life and Work. 2 vols. Harpers. 1910. 


Fifty Years of Electricity; Memories of an Electrical Engineer. 
Wireless Press. 1921. 

Electricity in Factories and Workshop. Lockwood. 1909. 

Spot and Are Welding. Lippincott. 1920. 

Electricity in Everyday Life. 3 vol. Collier. 1905. 

Modern Views of Electricity. 3d ed. rev. Macmillan. 1907. 

Electricity. Stokes. 1915. 

Modern Electric Practice. 6 vols. Greeham. 1917. 

The Electrical Transmission of Photographs. Pitman. 1921. 

The Story of Electricity; Historical Account and Sketches of the 
Pioneers. Marcy, 1919. 

A Century of Electricity. Houghton Mifflin. 1891. 

The Electric Furnace. Longmans. 1921. 

Elementary Lectures on Electric Discharges, Waves, and Impulses 
and Other Transient. McGraw Hill. 1914. 

Electricity and Matter. Yale Univ. Press. 

What is Electricity? Appleton. 1912. 

Electricity in the Service of Man. 2 vols. Cassill. 1918. 

Theory of Experimental Electricity. Putnam. 1912. 


Whittaker, E. T. 


Amer. Assoc. for 
the Advance- 
ment of Science 

Bailey, L. H. 


Bastian, H. C. 
Bateson, William 


aes aon 2 
Bergson, H. L. 
Bernard, H. M. 


Clodd, Edward 
Conklin, E. G. 
Cope, E. D. 

Coulter, J. M. 


3 


Darwin, C. R. 


Fiske, J. 


Haeckel, E. 


’ 


Herter, Christian 
A. 
Holmes, S. J. 


Howison, G.: H. 
Huntington, Ells- 
worth 


Jordan, D. S. 


Jordan, D. S. and 
Kellogg, V. 


Kellogg, V. 


Classified Bibliography 1189 


A History of the Theories of Ether and Electricity from the Age 
of Descartes to the Close of the Nineteenth Century. Longmans. 
1910, 


EVOLUTION 


Fifty Years of Darwinism. Modern Aspect of Evolution. Holt. 
1909. 


The Survival of the Unlike, a Collection of Evolution Essays. 
Macmillan. 1896. 

The Nature and Origin of Living Matter. Unwin. 1905. 

Mendel’s Principle of Heredity. Cambridge Press. 1909. 

Problems of Genetics. Yale Press. 1913. 

Creative Evolution. (Transl. by A. Mitchell) Holt. 1911. 

Some Neglected Factors in Evolution (An Essay of Constructive 
Biology). Putnam. 1911. 

A Primer of Evolution. Longmans. 1895. 

The Direction of Human Evolution. Scribners. 1921. 

The Primary Factors of Organic Evolution. Open Court. 1896. 

Evolution, Heredity and Eugenics. Univ. of Chicago Press. 1912. 

The Evolution of Sex in Plants. Univ. of Chicago Press. 1914. 

Fundamentals of Plant-breeding. Appleton. 1914. 

The Descent of Man and Selection in Relation to Sex. Murray. 
1901. 

The Origin of Species. Collier. 1909. 

Darwin and Modern Science—Essays in Commemoration of the 
Centenary of the Birth of Charles Darwin, and the 50th Anniver- 
sary of the Publication of the Origin of Species. Cambridge 
Press. “1909. 

The Influence of Darwin in Philosophy and Other Essays in Con- 
temporary Thought. Holt. 1910. 

Evolution in Modern Thought by Haeckel, Thomson, Weismann 
and others. Boni-Liveright. 1917. 

Evolution of the Earth and its Inhabitants—A Series of Lectures 
delivered at Yale University, 1916-17; Schuckert, Woodruff, 
Lull and Huntington. Yale Press. 1918. 

Darwinism and Other Essays. New. ed. rev. Houghton Mifflin 
Co. 1907. 

The Evolution of Man, a Popular Exposition of the Principal 
Points of Human Ontogeny and Phylogeny. 5th Edition. 
Putnam. 1894. 

The Riddle of the Universe at the Close of the 19th Century. 
Transl. by McCabe. Harper. 1900. 

Biological Aspect of Human Problems. Macmillan. 1911. 


The Trend of the Race; A Study of Present Tendencies in 
Biological Development of Civilized Mankind. Harcourt Brace. 
1921. 

The Limits of Evolution and Other Essays. 2d ed. rev. Mac- 
millan. 1904. 

World Power and Evolution. Yale Press. 1919. 


The Blood of the Nation—A Study of the Decay of Races through 
the Survival of the Unfit. Carlisle. 1912. 

Evolution and Animal Life—An Elementary Discussion of Facts, 
Processes, Laws, and Theories Relating to Life and Evoluton 
of Animals. Appleton. 1907. 

Darwinism of Today. <A Discussion of Present Day Scientific 
Criticism of the Darwinism Selection Theory, Etc. Holt. 1907. 


1190 


Locy, W. 
Morgan, T. H. 


3 


Nasmyth, H. P. 
Osborn, H. F. 


Patten, W. 
Poulton, E. B. 


Ritter 
Romanes, G. J. 


Thomson, J. A. 


Bonney, T. G. 

Chamberlin and 
Salisbury 

Dana, J. D. 


b] 
3 


Ford, W. E. 
Dutton, E. E. 
Fraser, C. C. 
Geikie, J. 
Hobbs, W. H. 
Joly, John 


Jordan, D. S. 
Kunz, G. F. 


Russell, I. C. 


MST e TT Neer | 
Taylor, J. E. 


Wright, G. F. 


Bigelow, F. H. 


Douglass, A. E. 
Fenel, W. 

Geddes, A. E. Mc. 
Humphreys, W. J. 
Huntington, E. 
McAdie, A. G. 
Milham, W. J. 
Moore, W. L. 
Moore, Sir J. 


Classified Bibliography 


Biology and Its Makers. Macmillan. 1917. 

Evolution and Adaptation. Macmillan. 1903. 

A Critique of the Theory of Evolution. (Lecture delivered at 
Princeton Univ.) Princeton Press. 1916. 

Social Evolution and the Darwin Theory. Putnam. 1916. 

The Origin and Evolution of Life—on the Theory of Action, 
Reaction, and Interaction of Energy. Scribner. 1917. 

From the Greeks to Darwin; An Outline of the Development of 
the Evolution Idea. Macmillan. 1894. 

Men of the Old Stone Age; Their Environment, Life and Art. 
Scribner. 1919. 

The Grand Strategy of Evolution; The Social Philosophy of a 
Biologist. Badger. 1920. 

Charles Darwin and the Origin of Species, Addresses, etc., in 
America and England. Longmans, Green. 1909. 

The Probable Infinity of Nature and Life. Badger. 1918. 

Mental Evolution in Man; origin of Human Faculty. Appleton. 
1902. 

The System of Animated Nature. (Clifford lectures.) Holt. 1920. 


GEOLOGY 


Volcanoes—Their Structure and Significance. Putnam. 1906. 
Geology. 3 vols. Holt. 1904-06. 


Corals and Coral Islands. Dodd Mead. 1890. 
The Geological Story Briefly Told. Am. Book. 1903. 
System of Mineralogy. Wiley. 1915. 


Earthquakes in the Light of the New Seismology. Putnam. 1904. 

Secrets of the Earth. Crowell. 1921. 

Founders of Geology. Macmillan. 1906. 

Earth Evolution and its Facial Expression. Macmillan. 1921. 

Radio-activity and Geology, an Account of the Influence of Radio- 
active Energy on Terrestrial History. Constall. 1909. 

The California Earthquake of 1906. Robertson. 1907. 

Gems and Precious Stones of North America. Scientific Pub. 
1890. 

Glaciers of North America. Ginn. 1897. 

Rivers of North America. Putnam. 1902. 

Geological Stories; A Series of Autobiographies in Chronological 
Order. Biggings. 1904. 

The Ice Age in North America. Bibliotheca Sacra Publ. Co. 1911. 


METEOROLOGY 


Meteorological Treatise on the Circulation and Radiation of the 
Atmospheres of the Earth and of the Sun. Wiley. 1915. 

Climate Cycles and Tree Growth. Carnegie Inst. 1919. 

A Popular Treatise on the Winds. Wiley. 1889. 

Meteorology; An Introductory Treatise. Blackie. 1921. 

Physics of the Air. Lippincott. 1920. 

Climatic Changes Their Nature and Causes. Yale Press. 1922. 

Principle of Aerography. Rand. 1917. 

Meteorology. Macmillan. 

Descriptive Meteorology. Appleton. 1910. 

Meteorology, Practical and Applied. Rebman. 1910. 


National Research Introductory Meteorology Prepared and Issued under the Auspices 


Council: 


of the Division of Geology and Geography. Yale Press. 1918, 


Redway, J. W. 
Ward, R. DeC. 


Clark,’ C. H. 

Cole, M. J., Cross, 
M. L. 

Ealand, C. A. 


Gage, S. H. 
Guyer, M. F. 


Marshall, C. E. 
Spitta, E. J. 
Stokes, A. C. 
Ward, J. J. 


Whipple, G. C. 


Classified Bibliography 1191 


Handbook of Meteorology. Wiley. 1921. 
Climate Considered Especially in Relation to Man. Putnam. 1908. 


MICROSCOPY 


Practical Methods in Microscopy. Heath. 1896. 
Modern Microscopy. Chicago Medical Society. 1912. 


The Romance of the Microscope: An Interesting Description of its 
Use in all Branches of Science. Lippincott. 1921. 

Microscope. Comstock. 13th ed. 1920. 

Animal Micrology: Practical Exercises in Zoological Micro- 
Technique. Univ. of Chicago Press. 1917. 

Microbiology; A Textbook of Micro-Organisms, General and 
Applied. Blakiston. 1921. 

Microscope: Its Construction, Theory and Use of the Microscope. 
Murray, 1907. 

Aquatic Microscope for Beginner, or Common Objects from the 
Ponds and Ditches. Wiley. 1918. 

Minute Marvels of Nature, Being Some Revelations of the Micro- 
scope exhibited by Photo-Microscope. Putnam. 1908. 

Microscopy of Drinking Water. Wiley. 1914. 


NATURAL PHILOSOPHY AND HISTORY OF SCIENCE 


Boutroux, E. 


Elliott, H. S. R. 
Enrique, F. 
Henderson, L. J. 
Jordan, D. S. 


Mivart, St. G. J. 
Morgan, C. L. 
Ostwald, W. 
Pearson, K. 
Poincaré, H. 


Thomson, J. A. 
Whetham, W. C. D. 
Whitehead, A. N. 


b] 


Bjerknes, V. F. K., 
et al. 

Buchanan, J. Y. 
Darwin, G. 
Hartwig, G. 
Howell, G. C. L. 
Jenkins, J. T. 
Murray, J. 

Verrill, A. H. 


Natural Law in Science and Philosophy. Trans. by F. Rothwell. 
Macmillan. 1914. 

Modern Science and Materialism. Longmans. 1919. 

Problems of Science. Trans. by K. Royce. Open Court. 1914. 

The Order of Nature. Harvard Press. 1917. 

Stability of Truth. A discussion of reality as related to thought 
and action. Holt. 1911. 

The Groundwork of Science. Putnam. 1898. 

The Interpretation of Nature. Putnam. 1906. 

Natural Philosophy. Trans. by T. Seltzer. Holt. 1910. 

The Grammar of Science. Black. 1911. 

The Foundation of Science: Science and Hypothesis, The Value 
of Science, Science and Method. Trans. by G. B. Halsted, 
Science Press. 1921. 

The System of Animate Nature. (Gifford Lectures.) 1915. 

The Foundation of Science. Dodge, 1912. 

The Concepts of Nature. Cambridge Univ. 1920. 

An Inquiry concerning the Principles of Natural Knowledge. 
Cambridge Press. 1919. 


OCEANOGRAPHY 


Dynamic Meteorology and Hydrography. Carnegie Inst. 1910. 
Scientific Papers. Vol. 1. Putnam. 1913. 

Tides. (Lowell Lectures.) Houghton Mifflin. 

Sea and Its Living Wonders. Longmans. 

Ocean Research and Great Fisheries. Oxford. 1922. 

Text-book of Oceanography. Dutton. 1921. 

Depths of the Ocean. Macmillan. 1912. 

Ocean and its Mysteries. Duffield. 1916. 


1192 


Davies, A. M. 
Loomis, F. B. 


Osborn, H. F. 


> 


Quennell, M., & C. 
H. B. 


William, H. B. 


Willis, Bailey 
Wood, H. 


Bayliss, W. M. 
Cannon, W. B. 


Halliburton, W. D. 

Hough and Sedg- 
wick 

Howell, W. H. 

Loeb, J. 


Macleod, J., et al. 
Pope, A. E. 
Reese, A. M. 
Roberts, M. 
Starling, E. H. 
Sternberg, G. M. 


Bandler, S. 
Benedict, F. G. 

Carpenter, T. M. 
Berman, L. 
Broadhurst, J. 
Carroll, R. S. 
Doane, R. W. 
Egbert, S. 

Ellis, C. 

MacLeod, C. L. 
Emerson, W. 
Fisher, I. 

Fitch, W. E. 
Halliburton, W. E. 
Harrow, B. 
Lusk, G. 
McCollum, E. V. 
Nutting, M. A. 

Dock, L. L. 
Richards, E. H. 

Woodman, A. G. 


Classified Bibliography 


PALHZONTOLOGY 


Introduction to Paleontology. Van Nostrand. 1920. 

Hunting Extinct Animals in the Patagonian Pampas. Dodd. 
1913. 

The Age of Mammals. Macmillan. 1910. 

Man of the Old Stone Age—Their Environments, Life and Art. 
Scribners. 1919. 

Everyday Life in the Old Stone Age. Putnam. 1922. 


Everyday Life in the Bronze and Copper Age. Putnam. 1923. 

Geological Biology. An Introduction to the Geological History 
of Organisms. Holt. 1895. 

Paleontology. Carnegie Inst. 1913. 

Paleontology. Putnam. 1919. 


PHYSIOLOGY 


Principle of General Physiology. Longmans. 1919. 

Bodily Changes in Pain, Hunger, Fear and Rage. Appleton. 
1920. 

Physiology and National Needs. Dutton. 1920. 


Human Mechanism. Ginn & Co. 1918. 

Physiology for Medical Students and Physicians. Saunders. 1918. 

An Introduction to Comparative Physiology of the Brain and 
Comparative Psychology. Putnam. 1900. 

Physiology and Biochemistry in Modern Medicine. Mosby. 1918. 

Essentials of Anatomy and Physiology. Putnam. 1922. 

An Introduction to Vertebrate Embryology. Putnam. 1904. 

Warfare in the Human Body. Dutton. 1921. 

Principle of Human Physiology. Lea. 1920. 

Infection and Immunity in the Cause and Prevention of Infec- 
tious Diseases. Putnam. 1903. 


HEALTH AND PHYSIOLOGY 


Endocrines. Saunders. 1920. 
Food Ingestion and Energy Transformation. Carnegie Inst. 1918. 


Glands Regulating Personality. Macmillan. 1921. 
Home and Community Hygiene. Lippincott. 1918. 
Mastery of Nervousness. 3d ed. Macmillan. 1918. 
Insects and Diseases. Holt. 1910. 

Hygiene and Sanitation. Lea and Febiger. 1916. 
Vital Factors of Food. Van Nostrand. 1921. 


Nutrition and Growth in Children. Appleton. 1922. 
How to Live. 15th ed. Funk. 1919. 

Dietotherapy. 3 vols. Appleton. 1918. 

Physiology and National Needs. Dutton. 1920. 
Vitamin—KEssential Food Factors. Dutton. 1921. 
Glands in Health and Disease. Dutton. 1922. 
Science of Nutrition. Saunders. 1920. 

Newer Knowledge of Nutrition. Macmillan. 1922. 
A History of Nursing. 4 vols. Putnam. 1907-1812. 


Air, Water and Food from a Sanitary Point of View. Wiley. 
1904. 


Roseman, M. J. 
Sherman, H. C. 
Smith, S. L. 


Exercises: 
Camp, W. C. 


Hutchinson, W. 
McKenzie, R. J. 


Sleep: 


Powell, L. P. 
Shepard, J. F. 


Sidis, B. 


Angell, J. R. 


’ 


Baldwin, J. M. 
Brett, G. S. 
Dewey, John 


eee ey Ae, 
Dresser, H. W. 
Goddard, H. H. 


Hoffman, F. S. 
Holt, E. B. 
James, William 


> 


Ladd, G. T. 
McDougall, W. 
Merz, J. T. 
Miinsterberg, H. 
Robinson, J. H. 
Russell, B. A. 
Sidis, Boris 


Stoddard, W. H. B. 
Van Norden, C. 


Watson, J. B. 


Yerkes, R. M. 


Classified Bibliography 1193 


Disinfection and Disinfectants. Blakiston. 1902. 
Vitamins. Chemical Cat. Co. 1922. 


Handbook in Health and How to Keep It. Appleton. 1920. 
Exercise and Health. Outing Pub. 1911. 
Exercise in Education and Medicine. Saunders. 1915. 


The Art of Natural Sleep. Putnam. 1908. 

The Circulation and Sleep. An Experimental Investigation. 
Maemillan. 1914. 

An Experimental Study of Sleep. Badger. 1909. 


PSYCHOLOGY 


Chapters from Modern Psychology. Longmans, Green. 1912. 

The Relation of Structural and Functional Psychology to Philos- 
ophy. Univ. Chicago Press. 1903. 

The Story of the Mind. Appleton. 1902. 

History of Psychology. 3 vols. Macmillan. 1921. 

Human Nature and Conduct. Holt. 1921. 

Psychology and Social Practice. Univ. Chicago Press. 1901. 

Human Efficiency: A Psychology Study of Modern Problems. 
Putnam. 1912. 

Psychology of the Normal and Subnormal. Dodd Mead & Co. 
i919: 

Psychology and Common Life. Putnam. 1903. 

The Freudian Wish and Its Place in Ethics. Holt. 1915. 

The Principles of Psychology. Holt. 1905. 

The Varieties of Religious Experiences—A Study of Human 
Nature. Longmans. 1917. 

Philosophy of Mind. Scribner. 1895. 

The Group Mind. Putnam. 1922. 

A Fragment on the Human Mind. Blackwood. 1919. 

Psychology and Life. Houghton Mifflin Co. 1899. 

The Mind in the Making. Harper. 1921. 

The Analysis of Mind. Unwin. 1921. 

The Foundation of Normal and Abnormal Psychology. Badger. 
1914. 

Mind and Its Disorders. Blakiston. 1919. 

The Psychic Factor—An Outline of Psychology. Appleton. 
1894. 

Psychology from the Standpoint of a Behaviorist. Lippincott. 
1919; 

Introduction to Psychology. Holt. 1911. 


Psycho-Analysis: 


Diene tl. C. 
Dunlap, K. 
Freud, S. 

ss ee, 
Green, G. H: 
Piister,. ©), 


History and Practice of Psycho-Analysis. Badger. 1920. 
Mysticism, Freudianism and Scientific Psychology. Mosby. 1920. 
Dream Psychology. McCann. 1920. 

General Introduction to Psycho-Analysis. Boni & Liveright. 1920. 
Psychanalysis in the Class-room. Putnam. 1921. 
Psychoanalysis in the Service of Education. Kempton, 1922. 


Psychic Science: 


Bassett, Sir W. 


On the Threshold of the Unseen; An Examination of the Phe- 
nomena of Spiritualism. Dutton. 1917. 


1194 


Bennett, E. T. 


Carrington, H. 


’ 


Crookes, Sir W. 
Hyslop, J. H. 


Jastrow, J. 
Lodge, Sir Oliver 


3 
Lombroso, C. 


Myers, Ff. .W; -H. 


Amundsen, R. 
Peary, R. E. 


Edelman, P. E. 
Fleming, J. A. 


Jansky, C. M. 
Marx, Hines, & 
Van Muffling, A. 
Stone, E. W. 
Towers, W. K. 


Van Deventer, H. 
R. 


Bird, J. M. 
Bolton, L. 
Carmichael, R. D. 
Carr, H. W. 
Carns, ok: 
Eddington, A. S. 
Einstein, A. 


Haldane, R. B. 
Harrow, B. 


Lorentz, H. A. 
Moszkowski, A. 


Poor, C. iL. 


Classified Bibliography 


Psychic Phenomena; A Brief Account of the Psychical Research. 
Foreword by Sir Oliver Lodge. Brentano. 1909. 

Psychical Phenomena and the War. Dodd Mead Co. 1918. 

The Coming Science. Intr. by J. H. Hyslop. Dodd Mead Co. 
1920. 

Researches into the Phenomena of Modern Spiritualism. 1904. 

Contact with the Other World; Latest Evidence as to Communica- 
tion with the Dead. Century. 1919. 

Fact and Fables in Psychology. Houghton Mifflin. 1900. 

The Survival of Man; A Study in Unrecognized Human Faculty. 
Doran. 1920. 

Survival of Man. Moffat. 1907. 

After Death—What? Small. 1909. 

Human Personality and Its Survival of Bodily Death. 2 vols. 
Longmans. 1920. 


POLAR EXPLORATION 


The South Pole. Trans. by C. G. Chater. 2 vols. Murray. 1913. 
The North Pole. Introd. by Theodore Roosevelt. Stokes Co. 
1910. 


RADIO 


Experimental Wireless Stations. Henley. 1922. 

The Principle of Electric Waves—Telegraphy and Telephony. 
Longmans. 1919. 

Principles of Radio-Telegraphy. McGraw Hill. 1919. 


Radio Reception. Putnam. 1922. 

Elements of Radio-Telegraphy. Van Nostrand. 1919. 

Masters of Space. (Morse, Thompson, Bell, Marconi, Carty.) 
Harper. 1917. 

Telephonology. 38d ed. McGraw Hill. 1912. 


RELATIVITY 


Einstein’s Theories of Relativity and Gravitation. Sci. Amer. 
Pub. 1921. 

An Introduction to the Theory of Relativity. Methuen. 1921. 

The Theory of Relativity. Wiley. 1920. 

The General Principle of Relativity in its Philosophical Aspect. 
Macmillan. 1920. 

The Principle of Relativity in the Light of the Philosophy of 
Science. Open Court Co. 1913. 

Space, Time and Gravitation; An Outline of the General Rela- 
tivity Theory. Cambridge Press. 1920. 

Relativity, the Special and General Theory; A Popular Exposi- 
tion. Trans. by R. W. Lawson. Holt. 1921. 

The Reign of Relativity.. Murray. 1921. 

From Newton to Einstein; A Changing Conception of the Uni- 
verse. Van Nostrand. 1921. 

The Einstein Theory of Relativity—A Concise Statement. 
Brentano. 1920. 

Einstein, the Searcher, His Work Explained from Dialogues with 
Einstein. Methuen. 1921. 

Gravitation vs. Relativity. Putnam. 1922. 


Classified Bibliography 1195 


Rougier, L. A. P. Philosophy and the New Physics; An Essay in the Relativity 
Theory and the Theory of Quanta. Trans. by M. Masius. Blakis- 

ton. 1921. 
Tolman, R. C. The Theory of the Relativity of Motion. Univ. Calif. Press. 1921. 


HISTORY OF SCIENCE 


Dana, E. S., et al. Century of Science in America. Yale Press. 1918. 


Merz, J. T. A History of European Thought in the Nineteenth Century. 
Blackwood. 1903-12. 

Singer, C. T. Studies in the History of Science. 2 vols. Oxford Press. 1916-18. 

Werkes, oi. New World of Science. Century. 1920. 


WHAT SCIENCE MEANS FOR MAN 


Campbell, N. R. What Is Science? Methuen. 1921. 

Grazebrook, R. T. Science and Industry. Putnam. 1917. 

Merz, J. T. Religion and Science. Blackwood. 1915. 

Mills, J. The Realities of Modern Science. Macmillan. 1919. 

Osler, Sin W. The Old Humanities and the New Science. Houghton Mifflin 
Co. 1920. 

Ritter, W. E. Higher Usefulness of Science. Badger. 1918. 

Soddy, F. Science and Life. Dutton. 1920. 

Veblin, T. B. Place of Science in Modern Civilization. Heubsch. 1919. 

Westaway, F. W. Science and Theology; their Common Aims and Methods. Blackie. 
1920. 


GENERAL ZOOLOGY 


Beddard, F. E. Book of Whales. Putnam. 1900. 
Berridge, W. S. Wonders of Animal Life. Stokes. 1916. 
Calkins, G. N. The Protozoa. Macmillan. 1901. 
Cambridge Natu- 
ral History Cambridge Natural History. 10 vols. 1895-1909. 
Comstock, J. H. Manual of Insects. Comstock. 
Davenport, C. B. Experimental Morphology. 2 vols. Macmillan. 1895. 
Howard, L. O. The Insect Book. Doubleday Page Co. 1901. 
Jordan, D. S. Fishes. Holt. 1907. 
Keaston, C. Wild Life Across the World. Intro. by Theodore Roosevelt. Hod- 
der and Stoughton. 1914. 
Kellogg, V. American Insects. Holt. 1908. 
Lutz, F. E. The Field Book of Insects. Putnam. 1921. 
Mathews, F. S. Field Book of Birds and Their Music. Putnam. 1916. 
—————_, —.—. The Nature Library. 10 vols. Doubleday Page Co. 1904-05. 
Paget, Stephen Experiments in Animals. Intro. by Lord Lister. Putnam. 1903. 
Thomson, J. A. The Study of Animal Life. Scribner. 1905. 


Wilson, E. B. The Cell in Development and Inheritance. Macmillan. 1900. 


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he i age 


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nee i. wavy ‘= 


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4 
t Rj 
) r 
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ae, 
ae | " 
ps GA 
ly Mi 
; : iy 
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aces 
RA? 0S Tg 
" ‘ 
1 
i 
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INDEX 


1197 


ek 


aad |} 7 ; ion Si 


oa uy Mi Ay ie : 
i | 


INDEX 


A 


Abiogenesis, 877 

** Acquired characters,’ 373-379 

Adaptations of animals (see Animals) 

Aerial life, 129 

Aeroplane, commercial, 849 (see also Air- 
craft) 

——first to fly, 843 

AMsop prawn, colour-change in, 142 

Africa joined to S. America, 97 

Agassiz, Louis, 67 

Age, Bronze, 173 

—— Metal, 173 

——Stone, 172 

Air, 1148 

——Failure of some animals to conquer, 87 

——sounding the upper, 765 

——“worked” for raw materials, 757 

Aircraft, astounding performances of, 846 

——the future of, 863 

Airships, 859, 860 

Albatross, the, 131 

Algol, a star of special interest, 41 

Alpha Centauri, one of the nearest stars, 10 

Alpha rays, 259 

Alps, making of the, 932 

Amecebe, 64 

Amphibians, 215, 1018 

——sgiant, 94 

——air-breathing, 84 

——first known, 93 

——first use of voice, 96 

——golden age of, 94 

Anabolism, 1045 

Anemograph Pressure Tube, 778 

Aniline dyes from coal-tar, 751 

Animal behaviour, 74, 240 

——heat, 480, 1002 

——life, of a country, changes in, 192 

——life through the ages, 107, 108 

——-structure, 302 

Animals (see also under Birds—Insects— 
Mammals—etc. ) 

——adaptations of, 115, 119 

——and plants, when established on the 
earth, 88 

——aquatic, tendency to invade the dry 
land, 84 

——beginning of land, 66 

——care of the young, 128, 486, 1073 

——change of colour in winter, 1068 


Animals, combats of, 483, 484 

——deep-sea, 982 

——difference between male and female, 
483 

——disguises of, 137 

——domesticated, 1107 

——effect of domestication, 1108 

——electric, 1004 

——evolution of, 93 

—-—experiments in locomotion, 202 

——family life of, 484, 492 

——food of, 64 

forming new habits, 200 

——freshwater, difficulties of, 125 

——genealogical tree of, 451 

—— hibernation of, 480, 1071 

——how safety of young secured, 86 

——hunting of, 1057 

——industries of, 1057 

——instruction of young, 487 

—— intelligence, 80 

——intricacy of architecture in, 302 

——light, nature of, 994, 996 

——luminous, 993 

——masking of, 148 

——minmicry of, 147 

——mode of living, 65 

——mutual aid of, 494 

——of the open sea, 121, 981 

——parasitic, 649 

—— play of, 230, 489, 490 

——polygamous, 484 

——ruminant, 473 

——-seashore, 983 

——sex dimorphism in, 483 

——storing food, 1058 

——struggle for existence, 137 

——‘‘summer sleep,” 1061 

——winter torpor, 1070 

——wits, using their, 224 

Animalcules, one-celled, 62 

Antelope, the, 466 

** Anti-bodies,”’ 107 

Ant, the Agricultural, of Texas, 1058 

——the Army, the ways of, 520 

——the Leaf-cutting, 518 

——the Leaf-cutting, nuptial flight of, 518 

——a Mediterranean, strange form of 
sociality in, 1072 

Ant-eater, the Great, 470 

——the Spiny, 453 

Ant-hill, the marvels of the, 516 


1199 


1200 


Anthrax or splenic fever, cause of, 893 

Anthropoid Apes, 105, 165, 171, 174 

Antitoxins, 1159 

Antlers, the story of, 474 

Ants, story of the, 512 

——castles of workers, 519 

——division of labour among, 516 

—— guests of, 517 

——industries of, 517 

——“‘‘keeping cattle,” 517 : 

——Mr. Beebe’s stories of, 518, 519 

——their toilet, 508 

——warlike expeditions of, 516 

——White (see Termites) 

Ape-man, the Java, 168 

Apes, the Anthropoid, 105, 165, 171, 174 

Apparitions, 575-579 

*‘Apports,”’ 587 

Aquatic ancestry of terrestrial vertebrates, 
evidence of, 97 

Arboreal, apprenticeship of Man, 165 

Archeopteryzx, the first bird, 100 

Argon and Neon, trapped from the air, 758 

Argus Pheasant, the, 434 

Art and literature, the place of, 1081 

Arthropods, air-breathing, 84 

Ass, domestic, descent of, 1111 

Astronomical Instruments, 47-51 

Astronomy, 9-47 

Atlantic, first flight across the, 844 

——cod banks of, 122 

Atlantis, fabled lost continent, 924 

Atmosphere, 765-768 

——a mixture of gases, 769 

——the early, of the earth, 60 

—w—-stratosphere and troposphere, 768 

Atmospheric circulations, 770 

Atmospheric disturbances, 768 

Atomic theory, the, 246 

Atoms, building up of, 263 

——disintegration of, 257, 265 

——energy of, 251, 287 

——one primordial substance, 254 

——structure of, 262 

——the world of, 245 

Austin, W. R. Roberts, 720 

Australia, first flight to, 844 

——joined to Asia, 97 

Autumn, biology of the, 1061 

——fruits, 1061 


B 
Bacilli, 888 
Bacteria, 64, 331, 601, 867-916 
——action on organic matter, 899 
——chemical problems of, 894 
——disease-carrying, 908 
——first use of the name, 874 
——forms of, 887 
——‘‘friendly”’ in the body, 329 
——general features of, 891 
——how carried, 910 
——in the body, 331 
—— influence of heat, cold, light, etc., 895 
——locomotion of, 890 
——luminous, 906, 992 
——manifold activity of, 904 
——multiplication and movement, 890 
——present-day knowledge of, 887 


Index 


Bacteria, protoplasm of, 893 
——belong to vegetable kingdom, 885 
——reproduction of, 892 

——of the sea, 973 

of the soil, 912 

species of, 903 

Backboneless animals, establishment of, 98 
Badger, story of the, 477 

Balance of nature, 643, 655 
Baleen Whale, 123 

Balloons, air observation by, 766 
Barnacles, 981 

Barnard, J. E., 312, 313 

Barry, Martin, 300 

“*Batesian,” mimicry, 147 

Bats, 132, 465, 466 

Bay of Fundy, tides at, 292 
Bayliss, Sir W., 311, 313, 736 
Beauty, the fact of, 1082 

Beaver, instinctive aptitudes, 226 
——story of the, 493 

Becquerel, discoveries of, 256 
Beebe, William, 518, 520, 652 
Beehive, the, 522 

Bees, communal life of, 522 
——honeycomb, 526 
——Humble, 528 

massacre of the males, 527 
nuptial flight, 526 
——nurseries of, 524 
——-pollination of flowers, 524 
——-sense of direction, 514 
——story of, 522 

——the swarm, 526 

Beetles, Burying, 533 

Berthelot, 61 

Beta rays, electrons, 259 
Betelgeux, the star, 37 

‘**Big Tree” of California, 71 
Biology, 673-699, 1080 

——of autumn, 1061 

——of spring, 1048 

——of summer, 1056 

——of winter, 1067 

Bird life, dawn of, 396 

Birds, beginning of, 100 

——and mammals, ancestors of, 99 
——before mammals, 102 
——hbehaviour of, 444 

——chicks and nestlings, 442 
——cleverness of, 446 
——co-operation of, 414 
——courtship of, 432 
——disguise of, 137 

——disguise of nests, 150 
domesticated, breedsand species of, 1127 
——‘educability,” 222 

——eggs, 443 

——evolution of, 395, 397 
——fertilise the soil, 395 
——first known, 100 

——flight of the, 403 
——flightless, 397 

——helping instinct, 411 
——homing, 431 

——importance of, in nature, 657 
——insect-eating, usefulness of, 657 
——instinct in, 221 
——inter-relations, 415 


Index 


Birds, masking of, 148 

mating of, 432 

——migration of, 425 

——mumicry of, 146 

——mind in, 220 

——mutual protection, 414 

natural history of, 395 

——nesting habits, 438 

nests, evolution of, 1058 

——our common, 415 

——parental care, 411 

——pet names of, 415 

——plumage, 432 

——reptilian features of, 101 

——reptilian stock, evolution from, 395 

——-senses of, 220, 221 

——skeleton of, 403 

——-social life of, 410 

——song of, 416, 437 

——voice of, 436 

——wits, using their, 224 

——young respond to warnings, 220 

Birds of Paradise, 434 

Blackbird, song of the, 416 

and Song Thrush, 417 

Blackcocks, tournament of, 434 

Black Grouse, 434 

Bladderwort entangling its prey, 613 

Blood, the, 329 

——action of one kind upon another, 331 

cells, 681, 1157 

circulation, 333 

complexity in the, 330 

——red corpuscles in, 331 

temperature of, 340 

——white corpuscles, 331 

Body and Mind, relation of, 241 

——machine and its work, 317-361 

——making of a, 67 

——muscular system of, 342-343 

——of man perfect machine, 317 

temperature in animals, 141 

——temperature of human, 1145 

——toxins and antitoxins in, 332 

traces of the past in the, 318 

——warfare in, 331 

Bolometer, the, 252 

Botany, the science of, 599-640 

Boyle, Robert, work on luminescence, 994 

Bragg, Sir William, 259, 268 

Brain, the, 344, 346, 541 

cells, 682 

health of the, 1153 

of man and ape compared, 239 

of man and gorilla, 105 

weight of gorilla’s, 156 

——weight of human, 156 

Breathing exercises, 1144 

Bronze Age, 173 

Brownian movement, 249, 311 . 

Buffalo, the Indian, domesticated breeds of, 
1114 

Bullfinch, the, 418 

Bunge, Prof., 756 

Burbank, Luther, 189 

Bustard, the Great, 435 

Butterflies, mimicry in, 146 

Butterfly, Leaf, 146 

Butterwort, how it traps its prey, 612 


VOL. 1vV—76 


1201 


C 


Cambrian period, 90 

Camel, the two-humped, 467 

Canes, Venatici, nebula in, 45 

Carbon, different forms of, 729 

——remarkable combining power of, 729 

Carboniferous Period, 93 

Carpenter’s, Dr. D. G. H., story of Uganda 
bug, 145 

Cat, domesticated, descent of, 1124 

——breeds of, 1125 

——puzzling features of, 1125 

Catalysts, the feature of, 732 

“Cats and clover,’’ 646 

Cattle, domestic, the descent of, 1113 

——humped, breeds of, 1114 

“Cave” men, 171 

Cells, brain, 682 

——many celled animals begin as “‘single 
cell,’ 68 

——microcosm of the, 306 

——showing division of labour, 344 

——-size of, 683 

——theory of, 305 

——white blood (phagocytes), defend the 
body, 1157 

Ceilulose, transformations of, 754 

Cenozoic Era, 89, 104 

Cerebellum or small brain, 348, 543 

Chalk, the story of, 944 

Chalones, 73 

Chamberlin, Prof.. on origin of earth, 58 

Chameleons, 143 

Chance, Mr. Edgar, 424 

Chemical change, nature of, 722 

——conjuring, 754 

——elements, the combinations of, 715 

——elements, the number of, 714 

Chemist, business of the, 716 

——as creator, 743-760 

——synthetic works of, 61 

Chemistry of the living creatures, 728 

——romance of, 713-740 

——science of, 1079 

Chimpanzee, the, 165 

——family life of, 485 

Chlorophyll, 63, 116 

——all life depends on, 605 

Cholera, cause of, 889 

Chromosomes, 306 

Church, Prof. A. H., 63, 66, 83 

Clairvoyance, 579, 585 

Clavius, crater on moon, 34 

Climate, changes in, 763 

——effect of changes, 192 

Clouds, 783, 786 

Clover, red, 647 . 

Coal burning, a chemical transformation, 
283 

Coal-measures, when laid down, 94 

——-source of, 285 

——story of, 942 

——substitutes, 284 

Coal-tar colours, 747, 751 

Collodion, manufacture of, 755 

Colloids, 735 

Colorado Beetle, destructiveness of, 655 

Colour blindness, 353 


1202 


Colour change in animals, 139-144 

——change in chameleons, 144 

vision, 353 

Coma Berenices, nebula in, 45 

Combustion, a chemical reaction, 26 

Comet of 1843, 36 

Comets, 35 

and nebule, what made of, 23 

Commensalism, 118, 149, 651 

Complexes, mental, 551 

Compounds and mixtures, 719 

Conductors of electric current, 271 

Conger-eels, 81 

Continents, how formed, 59 

movements of, 925 

once connected by land, 924 

Convergence, the superficial resemblance of 
unrelated types, 103 

Coot, the, 421 

Coral reefs, fishes that live among, 139 

Cormorants, effect of massacre of, 656 

fishing of the, 408 

Corncrake, the, 422 

Coronium, 17, 24 

Corpuscular radiation, 830 

Cotton-seed, utilisation of, 759 

Crab, adept in hide-and-seek game, 118 

hermit, 652 

Creatures, the characteristics of living, 703- 
709 

inter-relations of living, 643-670 

Crocodile, 100 

mode of life, 1020 

partnership of plovers with, 650 

Crookes, Sir William, 254 

experiments with radium, 254 

Crossland, Dr. Cyril, observations on 
chameleon, 144 

Crustaceans of the seashore, 986+ 

Crystals, 734, 938 

cause of the formation of, 734 

Ctenophores or “‘Sea Gooseberries,” habits 

" of, 120 

Cuckoo, story of the, 423 

Cuckoo-spit, the, 512 © 

Curie, Prof. and Mme., discover radium, 
256 

Curlew, the, 423 

Cuttlefishes discharging sepia, 118 

——tactics of, 149 


D 


Dalton, John, 246 

Darwin, Charles, 202, 365, 378, 387, 483, 
619, 645, 647, 669, 704 

on man’s origin, 105 

Darwinism, essence of, 366 

how stands today, 365-391 

what it means, 365 

Darwin’s Point, 158 

Davy, Sir Humphry, 725 

Day, becoming longer, 294 

the Martian, 295 

Dearborn, Prof., 259 

Death, beginning of natural, 71 

old age and, 695 

——ways of avoiding, 72 

Deep sea, biological conditions of the, 123 


Index 


Deep sea, colonising of the, 84 

——depth of the, 123 

extent of the, 124 

Deer, the Red, 476 

Descent of Man, Darwin’s, 155, 163, 388 

Devonian Period, 92, 93 

Dewar, Sir James, 725 

Diamonds, 735, 952 

Diatoms, inconceivable number of, 601 

Dietary, need of well-varied, 1139 

Digestion, process of, 323 

Dimorphism, sex, 483 

Dinosaurs, 99, 101 

Dodo, the, 398 

Dog, Prof. Watson’s bull-terrier, 227 

the domestic, its ancestors, 189 

Lord Avebury’s “ Van,” 227 

Dogs, domesticated, descent of, 1121 

different strains, 1121 

edible, 1124 

effect of selection in breeding, 1123 

Domesticated animals attacked by para- 
sites, 659 

Dominant and recessive qualities explained, 
381 

Dove, song of the, 418 

Dover, cliffs of, 945 

“Dowsing,” 584 

Dreams, Freud’s theory of, 557 

——interpretations of, 561-563 

Dredge, what it has revealed, 998 

Dromedary, the Arabian, 467 

Drosophila in mutating mood, 187 

Dubois, Raphael, experiments with mol- 
luses, 994 

Duckmole, the, 82, 453 

Dudley, Prof. W. R., 709 

Duncan, Prof. R. K., 193, 732 

Dynamo, the, what it does, 272, 798 


E 


Eagle, the Golden, 408 

Earth, the, 11 

——age of the, 267 

——beginning of the, 57 

crust of the, 921 

growth of the, 58, 920 

its revolution, 11 

——origin of the, 919 

primitive size of the, 920 

Professor Chamberlin on origin of the, 


58 
——pulled by moon, 290 
——slowing down, 290-294 
——travelling at prodigious speed, 11 
Earthquakes, 921, 929 
Earths, rare, and their uses, 736 
Earthworms, reflex action in, 77 
——promoters of vegetation, 645 
——the work of, 644 
Eel, story of the, 199 
——nmigration of the, 1055 
Ehrenberg’s work, 874 
Einstein, 288 
his prediction verified, 1041 
——theory, the, 1025-1042 
Electric and luminous organisms, 991-1007 
——catfish, the, 1005 


Index 


Electric circuits, 800 

Perel ty. ©. U0 

——current, alternating, 798 

——current, “‘continuous” or “direct,” 
799 

——current, distribution of, 802 

——eel, the, 1005 

——generating stations, 801 

—— generator, 799 

——heating, 817 

——lighting, 815 

——locomotives, power of, 809 

——ray, the, 1004 

——shock, 801 

——traction, 804 

——train, 805 

transformers, 802 

——welding, 818 

Electrical battery, 270 

——“‘cell,’’ 270 

——change occurs in all organisms, 676 

——engineering, outlook for, 793 

——induction, 797 

——power, transmission of, 796 

Electricity, 262, 264, 266 

——from waterfalls, 809 

——in animals, 1004 

——marvels of, 793-818 

——nature of, 269 

——storage of, 803 

——what a current is, 797 

Electrification of main railway lines, 807 

Electrified tramway, 800 

Electrolyte, dissociation of, 721 

Electro-magnetic wave, what it is, 828 

Electron, 255 

——a, “‘vortex”’ in ether, 288 

——discovery of, 257-261 

——nature of an, 288 

——-size of, 261 

——some experiments, 260 

——theory, 262 

Electron, velocity of, 260 

Element, an, 721 

——a distinctive spectrum, 22 

——valency of an, 716 

Elements, chemical, 265, 719 

——radio-active, 253 

——transmutation of, 726 

Elephant, the, 472 

——learning tricks, 229 

Elephants, camels, and llamas, the domes- 
tication of, 1126 

Elliott, Prof. Scott, 627 

Embryo, developing, 160, 162 

Embryos, resemblance in, 161 

Embryology (see Biology) 

Emotions, 358 

——influence on health, 358 

Energy, 267 

——an actual entity, 288 

——conservation of, 212, 674 

——dissipation of, 284 

——forms of, 282 

——indestructible, 282 

——kinetic and potential, 283 

——of falling water, 284 

——of the atom, 285 

——of the sun’s rays, 284 


1203 


Eocene Period, 92, 102 

Era, Cenozoic, 92 

——Mesozoic, 92 

——Paleozoic, 92 

Eras, geological, 91 

——table of various geological, 92 

Ether, 255 

——a hypothesis, 830 

——conception of, 256, 274 

—— Michelson and Morley experiment, 289, 
1037 

——‘“‘vortex”’ in, 288 

Ethnology, the science of, 1093-1104 

Evolution, anatomical evidence, 109 

——embryological evidence, 108 

——evidences of, 107 

——factors in, 109, 366 

——first steps, 64 

——going on, 185, 204 

——great acquisitions, 73 

——historical evidence of, 107 

——how it makes towards harmony and 
progress, 108 

——idea, a master key, 55 

——idea, acceptance of, 365 

—w—idea, applied to the chemical elements, 
35 


—w—idea, the three problems of, 368 
——inorganic, 55, 266 

——not necessarily progressive, 106 
——of feelings and emotions, 55 
——of instinctive behaviour, 80 
——of mind, 74 

——physiological evidence, 109 
——retrogressions, 669 

——steps in human, 177 

——story of, 55-111 

Evolutionary prospect for man, 186 
Evolving new variations, 106 
——system of nature, 105 

Exercise, value of, 1142 

Existence, the struggle for, 137-151 
Experimentation in play, 230 
Explosives, manufacture of high, 755, 758 


F 


Faraday, Michael, 725, 726, 738, 995 

——on luminescence of glow-worms, 996 

Fauna, origin of deep-sea, 124 

Fermentations caused by Bacteria, 888 

Ferments, 733, 900 

——and Bacteria, 900 

——chemical transformations, 733 

Fern, life-history of, 637 

——spore-cases of, 638 

Fertilisation, the process of, 629 

Fife, Davie, 191 

Fire-fly, light of the, 996 

——lItalian, 1001 

Fischer, Emil, 674 

Fishes, Miss G. White’s experiments with, 
P1Siwes 

——first establishments of, 98 

——flat, self-effacing habit of, 141 

—-—interesting ways of, 211 

——luminous, 998 

——mode of life, 1017 

—-—of the deep sea, their mode of life, 982 


1204 


Fishes, of the open sea, 980 

——of the seashore, 983 

——senses of, 210 

Fleming, Prof. J. A., 793 

Flight, problem of, solved four times by 
animals, 101, 130 

“Floating sea-meadows,” 121 

Flora, Carboniferous, 97 

Flowers, concerned with reproduction of 
higher plants, 628 

——cross-pollination, how effected, 632, 633 

——meaning of the, 628 

——methods of pollination, 630 

——parts of, 628 

——how they attract insects, 631 

——intoxicating nectar, 627 

——why they are bright, 629 

Fly, the, how it walks, 509 

Flying (see also Aircraft) 

——first flight across the Atlantic, 844 

——safety of, 862 

Flying Dragons, 87, 99 

BO PS 6. 

——Lemurs, 87 

—— Lizard, 130 

——Phalangers, 87, 130 

-——Squirrels, 130 

——Tree-toad, 130 

Food, bolus of, transport described, 325 

——calories of, 1136 

——how digested, 325 

——-proper digestion of, 1140 

——the energy of, 1134 

——three classes of, 1136 

——Vitamins, importance of, 1138 

Foraminifera, chalk-forming, 67 

Forbes, Dr. H. O., 438 

——-story of a flat spider, 144 

Forest primeval, 66 

Forests dwindling, 167 

Formative times, 92 

Fossils, use of, 88 

Foundations of the Universe, 245-271 

Foxes, cleverness of Arctic, 229 

Freshwaters, animal population of the, 84 

——colonised by gradual migration, 84 

Freud, Prof., 555, 557 

Frigate-bird, 435 

Frogs, common, parental care of, 217 

——Darwin’s, 218 

——development of, 1052 

——Prof. Yerkes’ experiments, 216 

Fruits, uses of, to the plants, 1063 

Fungi, 602, 609, 612 

——light production in, 992 


G 


Galileo, 299 

Galton, Sir Francis, 375, 380, 384 

Gamble, Prof., on colour-change in animals, 
142 

Gametes, ‘‘unit characters”’ in, 381 

Gamma rays, 259 

Gannet, the, 409 

Gases, liquefaction of, 724 

Gazelle, the, 466, 467 

Gems (see Precious stones) 

Geniuses and cranks, 378 


Index 


Geographical distribution undergoes great 
changes, 102 

Geological middle ages, 99 

Germ-cells, nature of, 69 

——plasm, complexity of, 379 

Germinal continuity, 384 

Geysers, 929 

Gibbon, the, 165 

Gibbons, family life of the, 485 

Gipsy Moth, destructiveness of, 656 

Giraffe, the, 374 

Glaciers, action of, 935 

Glands, adrenal, 336, 355 

——of internal secretion, evolution of, 73 

——pituitary, 357, 698 

——suprarenal (see adrenal) 

——the ductless, 355, 673, 691 

——thyroid, 356, 698 

Glow-worms, luminescence in, 996, 1001 

Goat, the domesticated, 1118 

Goldfinch, 418 

Gorilla, the, 165 

Gossamer showers caused by spiders, 1064 

Granite, the story of, 937 

Gravity, 26 

——a new view of, 1027 

Grebes, 421 

Grouse disease caused by parasites, 72 

Growth, ‘‘ripple-marks”’ of, 1046 

Gull, the Blackheaded, 421 

Gullery, the story of a, 661 


H 


Haber process for capturing nitrogen, 757 

Hallucinations or apparitions, 575 

Hamen, Louis de, 300 

Hare, the common, 468, 488 

——the mountain, seasonal changes of 
colour, 140 

Harvey, William, 307, 731 

Head, Flat-worm producing a new, 689 

Head-brains, establishment of, 73 

Headley, F. W., 404 

Health, the science of, 1133-1161 

——co-related with happiness, 1142 

——influence of emotions on, 358 

——physiology of, 1143 

Healthy-mindedness, 360 

Hearing, sense of, 353 

Heart, the, 332 

——‘‘beat”’ of, 333 

Heat, the nature of, 283 

Heather, 653 

Heavenly bodies, two classes of, 10 

Hedgehog, the, 479, 660 

Heidelberg Man, 168 

Helium, a story about, 738 

Helmholtz on origin of life, 61 

Heredity, 366, 369, 380 

Heritable novelties or variations, 110 

Hermit-crabs, masking of, 652 

——partnerships, 118 

Heron, the, 420 

Herring-gull, the, 201 : 

——breaking shells, 445 

Hertz, Heinrich, 827 

Hibernation of animals, 480, 1071 

Holmes, Prof. S. J., 234 


Index 


Homing of ants and bees, 513 

——of birds, 431 

Homo sapiens (see Man) 

Hormones, discovery of, 344, 354 

——the functions of, 355 

Hornbill, imprisonment of the, 439 

Horse, the, in ancient times, 1108 

Horses, British breeds of, 1110 

——domesticated, their descent, 1109 

——the Arab tribe, 1111 

——thoroughbred, 1111 

Housefly carries germs, 536 

Hudson, W. H., 411, 416, 440 

Huia, upper bill of the, 411 

Human institutions, evolution of, 56 

——progress factors in, 179, 180 

——trise and fall in, 172 

Humanoid race, transition from the, to the 
human, 167 

Humming-bird moths, 147 

Hunger in the open sea, 122 

Huxley, Julian S., 673, 707 

Hybrids, result of interbreeding, 384 

Hydatina, 68 

Hydra, 68 

Hygiene, 1154 


Ice ages, 97, 103 

Icebergs, 975 

Ichthyosaurs, the, 99 

Ideas, revolution in, 258 

Indigestion, causes of, 1140 

Individual, beginning of the, 307 

Individualities, multitude of, 704 

Infection, artificial, against disease, 1159 

Infusoria, 870, 873 

Infusorians, 66, 301 

Inheritance of disease, 374 

——the laws of, 360 

Inoculation, protective, 1159 

Insect world, the, 503-537 

Insects (see also under individual names) 

——adaptations, 503, 504 

——and balance of Nature, 536 

——and pollination of flowers, 630 

——antenne of, 507 

——compound eye of, 507 

——establishment of, 99 

——first appearance of, 93 

——-general characters of, 506 

——homing of, 513 

——how attracted to blossoms and flowers, 
630 

——how young are hatched, 533 

—— instincts and intelligence of, 511 

—— intelligent behaviour of, 514 

——life-histories of, 531 

——metamorphosis of, 534 

——pedigree of, 505 

——risks through multiplication of, 656 

——-species, number of, 503 

——speed of flight, 129 

——struggle for existence, 504 

——success of, 503 

——walking-stick, tactics of, 145 

——wingless, 121, 510 

——wings of, 510 


1205 


Insomnia, causes of, 1151 

Instinct in animals, 207, 511 

——1in insects, 511 

Instinctive aptitude in birds, 221 
——aptitude in mammals, 226 
——behaviour, instances of, 78, 79, 208 
Insulators, electric, 271 

Intelligence and reason, 239 
——co-operating with instinct, 223 
——in animals, 210, 223 

——in animals, why there is not more, 230 
——1in insects, 511 

Inter-relations in nature, 105 

——of living creatures, 643-670 
Invertebrates, establishment of, 90 
Invisible, demonstrating the, 723 

Ions, travelling atoms, 721 

Isle of Wight disease, 302 


J 


James, William, 175, 548 
Jansen, Z., 299 

Java ape-man, 168 

Jay, the, 419 

Jellyfish, the, 39, 73, 188 
Journal of the S.P.R., 576 
Joy, the cult of, 359 
Jupiter, the planet, 10 
——theories of origin of, 31 


K 


Kangaroo and its young, 128 

Katabolism, 1045 

Keith, Sir Arthur, 168, 170, 172, 325, 332, 
342, 349, 855, 1096 

Kekulé, 749 

Kelvin; Lord, 61, 266, 720 

Kestrel, hunting methods of the, 404 

King, Prof. William, 123 

Kirkman, F. B., 410 


L 


Lady-bug, eliminating scale insect, 656 

Lamarck, evolution theory of, 374 

Lamp filament, electric, 738 

Lamprey, mode of life of the, 1015 

Lamp-shell Lingula, 187 

Lancelet, mode of life of the, 1015 

Land and sea areas, interchange between, 
924 

——and water, distribution of, 923 

——disappearing below surface of ocean, 
924 

——flora, establishment of, 98 

Langmuir, Dr., 263 

Lankester, Sir E. Ray, 163, 222, 224, 234, 
658, 718, 927 

Laplace, theories of, 41, 57 

——philosophy of, 1083 

Lapwing, the, 422, 428 

Lark, the, 417 

Lashley, Dr. K. S., 432 

Lavoisier, 743 

Learning in animals, 76 

Leaves, luminescence of decaying, 992 

——withering, meaning of, 638 

Le Bon, Prof., 267 

Leeuwenhoek, work of, 300, 869 


1206 


Lemmings, story of the, 1066 

Lenard’s experiments, 255 

Levick, Dr. Murray, 399 

Leyden jar, the, 831 

Lichens, 610 

——double nature of, 653 

Liebig, Justus, 731, 750 

Life, abundance and insurgence of, 706 

——ancient, 91 

——haunts of, 83 

——higher manifestations of, 1085 

——1in other worlds, 28 

——lengthening span of, 697 

——lowest forms of, 59 

——making a home for, 59 

——mind and matter, relation between, 
1082 

——nature of, 673, 1084 

——origin on earth, theories of, 60, 675, 676 

——procession of, through the ages, 88-93 

——rhythm, 1045 

——slowly creeping upwards, 107 

——stages in development of cells, 631 

——theories of the origin of, 675, 676 

——ultimate molecule of, 718 

——units of, 679 

——world, of invisible, 299 

Light composed of rays of several colours, 21 

—-—measuring speed of, 24 

——progress in production of artificial, 737 

——speed of, 278 

——ultra-violet, 281 

——visible and invisible, 276 

——waves, 22, 255, 274, 276 

——waves, sorting out of, 278 

——what it consists of, 276 

Lingula, 98 

Linkages between one creature and another, 
649 

——Epizoic, 649 

Lithosphere, the, 59 

Liver, work of the, 328 

Liver-fluke, the, 301 

——life-story of, 666 

Living and non-living matter, distinction 
between, 675 

——creatures, the characteristics of, 703- 
709 

——creatures, first appearance of, 62 

——creatures, organisms, 82 

——creatures, origin of, 60 

Lizard, surrendering tail, 220 

——mode of life, 1021 

Llamas, the, 467 

Lockyer, Sir Norman, 24, 58 

Locusts, 534, 536 

Lodge, Sir Oliver, 267, 567, 794 

Loeb, Prof., 696 

Lowell, the late, Prof. Percival, 29 

Lower vertebrates, 1011-1022 

——evolution of, 1013 

Luidia, 81 

Lull, Prof. R. S., 103, 162, 164, 167, 656 

Lungs, the work of the, 338 


M 


MacBride, Prof. E. W., 375 
Magnet, the, 274 


Index 


**Magnetic field,’ the, 273, 797, 798, 828 
Magnetic storms, 20 

Magnetism, how it arises, 273, 274 
Magneto, 798 

Magpie, the, 419 

Malarial fever and the mosquito, 536 
Malpighi, Marcello, 302 

Mammals, 451-499 

——adaptations of, 469, 470 
——aerial, 465 

——and birds compared, 102 
——aquatic, 459 

——arboreal, 463 

——hbeginning of, 99, 451 

——brain of, 457 

——care of the young, 486 
——dexterity of, 226 

——egg-laying, 453 

——emergence from reptiles, 101 
——evolution of, 458 

——family life of, 484 
——food-getting among, 470 
——general characters of, 496 
——golden age of, 102 

——learning tricks, 229 

——many habitats of, 457 
——marsupial, 454 

——mind of, 225 

——modern types of, 452 
——mountain, 468 

——mutual aid in, 491 
——nocturnal, 477 

——of deserts and steppes, 466 
——origin of, 451 

——placental, 456 
——pouch-bearing, 455 
——protective adaptations, 476 
——ruminant, 473 

——sex dimorphism in, 483 
——small-brained replaced by large, 102 
——social, 491 

——subterranean, 461 

——weapons of, 474 

——variety among, 495 

Man, ancient skeletons, 171 

——and animal linkages, 658 
——and Primates, 164 
——antiquity of, 170 

——arboreal apprenticeship, 165 
——ascent of, 104, 155-180 
——compared with anthropoid apes, 155 
——derived from simian stock, 163 
——embryological, 159 
——Evolutionary, prospect for, 186 
——Heidelberg, 169, 174 
——Neanderthal, 169, 174 
——Neolithic, 172, 173 

——of feeling, William Jameson, 175 
——pedigree of, 164 
——physiological, 158 
——Piltdown, the, 170, 174 
——Prithecanthropus erectus, 168, 174 
——possible degeneration of, 186 
——primitive and modern compared, 177 
——recapitulation stages in, 159 
——stages of, 173 

——stands apart from animals, 104, 156 
——the natural inheritance of, 161 
——vestigial structures in, 158 


Index 


Manifestations, 592 

Mankind, races of, how they arose, 175 

Man’s body, a museum of relics, 105, 156 

facial expression, 105, 157 

——mental qualities, 163 

——-solidarity with rest of creation, 105 

Marconi Co. stations, 827 

Margarine, manufacture of, 754 

Mars, 10, 29 

——canals on, 30 

Materialisations, 582 

Materialism, the old-fashioned, 548 

Mathematics, an abstract science, 1079 

Mating time, the significance of, 386 

Matter, circulation of, 644, 731 

——conservation of, 743 

——difference between ‘‘non-living’’ and 
living things, 895 

——forms of, 716 

——fundamental unity of, 288, 716 

——has no spontaneity, 1086 

——living and lifeless, 673 

——new views of the constitution of, 264, 
266, 288 

——-space, time, and (see Einstein theory) 

Maxwell, Clerk, 724, 745, 828 

Mayfly, the, 511, 1052 

Medicine, advance in science of, 1156 

Medulla, the, 349, 543 

Men, “‘cave,”’ 171 

——primitive, 171 

——tentative, 168, 171 

Mendel, 371 

Mendelism, fundamental ideas in, 380 

——theory of “‘unit characters,’”’ 380, 381 

Mental conflicts, repression of, 554 

——disorders, 559 

——hygiene, 1154 

——processes, 549 

Mercury, the planet, 10 

Mesozoic Era, 89, 99 

Metabolism, 70, 1045 

Metal Ages, 173 

Metazoa, 67 

Metchnikoff, Prof., 140, 326, 699 

Meteorites, millions of, 35 

Meteoritic matter and the sun’s heat, 27 

——theory of earth’s origin, 919 

Meteorological recording instruments, 774 

——-service, the organisation of a, 774 

Meteorology, 763-789 

Meteors, 35 

Michelson & Morley experiments to detect 
ether, 289, 1037 

Microbes (see Bacteria) 

——the increasing mastery of, 1157 

Microcosm of the cell, 307 

Microscope, the, 299, 311 

——compound, 299 

——important discoveries by means of, 
300-308 

——manifold uses of, 308 

——the ultra-, 310 

Microscopic structure, beauty of, 313 

Microscopists, the early, 867 

Microscopy, the wonders of, 299-313 

Migration, beginning of, 103 

——of birds, 1072 

Milky Way, 13, 44 


1207 


Mind and body, relation of, 358 

——and matter, 546, 675 

——hbustle of, in animals, 238 

——complexes, importance of, 551 

——dawn of, in animals, 207-242 

——emotional experiences suppressed, 559 

essence of, 1086 

——evolution of, 74 

——human, what comprises natural in- 
heritance in, 544 

——in evolution, 541 

——influence on body, 358 

——matter the vehicle of, 1087 

——of amphibians, 215 

——of birds, 220 

——of mammals, 225 

——of the minnow, 213 

——of monkeys, 232 

——of reptiles, 218 

——the science of the, 541-563 

——‘‘structure”’ of the, 550 

——the unconscious, 551 

Miocene Period, 92, 102 

Missel-thrush, song of, 417 

Mists and fogs, cause of, 786 

“Moa,” the giant running bird, 398 

Modifications and variations, 373 

——transmission of, 374. 

Mole, the, 461 

Molecular movement made visible, 248 - 

Molecules, 248, 249, 251, 748 

——and atoms, 721 

Molluscs of the seashore, 985 

Monkey-ape-man line, 104 

Monkeys, activity of, 233 

——American, 164 

——Brehm’s story of, 492 

——dexterity of, 226 

——experimenting with, 236 

——imitation in, 237 

——intelligence of, 239 

— —keen senses of, 232 

——mind of, 232 

——Old World, 164 

——power of manipulation, 232 

——quick to learn, 234 

——race of, emerge, 101 

——story of, 235, 236 

Monsoon, the Indian, 773 

Month becoming shorter, 295 

Moon, 12, 32 

——a dead world, 32, 35 

——action in causing tides, 291 

——‘craters”’ on, 34 

——eclipse of the, 12 

——mountains on the, 34 

——origin of, 292 

——receding, 293 

——temperature of, 34 

Moons which attend the planets, 32 

Moorhen, Prof. Morgan’s experiments with 
a, 223 

Morgan, Prof. Lloyd, 210, 222, 223 

Moseley, Mr., arranges atomic numbers, 264 

Mosquito and malarial fever, 536 

——its mode of life, 1051 

Moss, cause of luminosity in, 992 

Moth and the candle, 78 

Moths, the Yucca, 78 


1208 


Moulton, Prof., 58 

Mountains, destruction of, 934 
——of Scotland and Norway, 933 
——the making of, 930 

Mouse, the Japanese Dancing, 228 
——the Snow, 469 

Mudfish of Australia, 200 
Mudskipper, habits of, 214 

Mule, the, descent of, 1112 
Miiller, Dr. F., work of, 870 
Murray, Professor Gilbert, 572 
Muscles, the, 343 

Muscular development, value of, 1141 
Mussles (freshwater), 649 
Mutations, 110, 372 

——theory of, 369 

Mutual help in animals, 494 
——in birds, 410 

——in insects, 516 

Myers, F. W. H., 580 


N 


Natural History: 

——Birds, 393-447 

——Botany, 599-640 

Insects, 503-537 

——Lower Vertebrates, 1011 

——Mammals, 452-498 

——natural selection, Darwin's theory of, 
366 

——-selection, 
tions, 385 

——-selection, proof of, 390 

Nature, economy of, 644 

——evolving system of, 105 

Neanderthal species of man, 169 

Nebule, spiral, nature of, 40 

Nebular hypothesis, 40, 57 

Nekton, animals of the open sea, 121 

N 

N 

N 


post-Darwinian investiga- 


eoceratodus, 200 

Veolithic culture, 172 

eptune, 10 

Nerve cells, 345 

——thrills, accompanied by electricity, 346 
Nervous system, care of, 1153 
——system, complexity of, 344, 347 
Neurasthenia, 1155 

Newcomb, Simon, 9 

Newton, Isaac, 290, 1027, 1040 
——Professor, 414 

Niagara Falls, 809 

Night blindness, 381 

Nightingale, song of the, 416 

Nitrates and the soil, 756 

Nitrogen, Haber process, capturing of, 755 
Noctiluca, 121 

Notochord, the, 161 

Novelties, Darwin’s interest in, 371 
Nurture, human, discussed, 376 


O 


Observatory, the modern, 48 
Oceanography, 959-987 
Oceans, the, 924 

Octopus, the, 986 

Opossum, the, 455 

Opsonins, theory of, 1158 
Orang, the, 165 


Index 


Orang, family life of the, 485 

Orchid, curious method of pollination, 627 
Ordovician Period, 92 

Organic compounds, artificial production, 


——evolution, what it means, 55 

——evolution, a continuous process, 56 

Organisms, 62 

——electric and luminous, 991-1007 

Origin of Species, The, 388 

Osborne, Prof. H. F., 52, 458 

Oscillations, damped, 832 

——undamped, 832 

Ostrich tribe, 399 

Otter, story of the, 487 

Owen, Sir Richard, on man’s structure, 156 

Owls, the burrowing, living with prairie 
dogs, 415 

Oxygen produced by green plants, 600, 643 


1 


Paleolithic culture, 172 

——implements, 171 

Paleozoic era, 89, 92 

Palmistry, childish make-believe, 349 

Palolo-worms, mode of life, 72, 1047 

Paper, manufacture of, 754 

Parasites, 71 é 

——and pearls, 668 

——easygoing life of, 106 

——flowering, and saprophytes, 610 

——the hosts of, 664 

——what they do to their hosts, 665 

Parasitism, 106 

Parental care, 81, 119 

Parrot, the Nestor, 201 

Parthenogenesis, 688 

Partnership between animals, 650 

——mutually beneficial between different 
creatures, 106 

Partridge, a model father, 418 

Pasteur, 300, 677 

Pavlov, Prof., 358 

Pearly Nautilus, 187 

Pearls formed by parasites, 668 

——what they are, 951 

Pelagic plants, 120 

Penguins, their strange ways, 399, 979 

Peregrine falcon, the, 407 

Perfumes, artificial, 751 

Peripatus, 81, 128 

Permian Ice age, 96 

Perrin, Prof., 250 

Personality bound up with nervous system, 
347 

Petrels, sharing holes with lizards, 415 

Petrie, Prof. Flinders, 176 

Phagocytes (white blood-cells) 
microbes, 1157 

Phantoms, instances of, 575 

Pheasants, the defence of young, 418 

Philip, Prof. J. C., 723 

Philosophy of science, 1177 

Phosphorescence, 280 

Phrenology, 349 

Physics, science of, 245-295, 1079 

Physiology and psychology join hands, 360 

——science of, 317-361, 1081 


digest 


Index 


Pickering, Prof. W. H., views on Mars, 30 

——views on the moon, 32 

Pigeons, domestic breeds of, 189, 1128 

Pigs, derived from two stocks, 1120 

——domesticated, 1120 

Piltdown man, 170 

Pineal eye, 320 

Pithecanthropus erectus, 168 

‘“*Planetoids,”’ 3 

Planets, the (and see under individual 
names), 10, 12, 28 

Plankton, animals of the open sea, 121, 122 

Plant, the pitcher, 613 

—-—life, variety of, 601 

——life wonders of, 599 

——what the green plant does, 605 

Plants, annuals and perennials, 638 

——architecture of, 604 

——capture sunlight, 606 

——cause of the light in luminous, 991 

——characteristic odours of, 626 

——common characters of, 603 

——do they sleep ? 624 

——essential work of, 605 

——evolution of, 189, 599, 638 

——first, 65, 602 

——first establishment of, 98 

——flowering, when first established, 93 

——food of, 600, 603 

——function of the leaf, 639 

——grafting and budding, 636 

——growing from germinating seeds, 629 

——how they protect themselves, 626 

——importance of minute, 600 

——insectivorous, 612 

——life of, 639 

——one-celled, 62 

——periodic movement of, 625 

——photosynthesis of, 607 

——protection against herbiferous animals, 
627 

——reproduction of, 627 

——sensitive, 622 

—— sensory organs of, 619 

——tactics of, 616 

——travels of, 635 

——use of, 627 

——ways of meeting the winter, 1071 

——weapons of, 626 

——wind and water carrying seeds of, 635 

——without seeds, 636 

——wonderful adaptations of, 616 

Pleistocene age, 92, 103 

Plesiosaurs, the, 99 

Pliocene period, 103 

Plumage coloration, 433 

Polar bear, mode of life, 984 

——using its wits, 229 

Pollination of flowers, 632 

Ponting, H. G., 400 

Population of the world, 1102 

Potash, the supply of, 758 

Poulton, Prof., experiment with caterpil- 
lars, 140 

Praying Mantis, experiments on, 138 

Pre-Cambrian Eras, 90 

Precious stones, 948 

——legends of, 955 

——remarkable histories of, 954 


1209 


Primate stem, divergence from main stem’ 
164 

Primates, the, 164, 174 

——divergence from other orders, 171 

——emergence of, 101 

——whence they sprang, 164 

Proteins, 674 

——how formed, 728 

Proterozoic ages, 92 

Protists, 63, 599 

Protoplasm, the basis of life, 306, 678, 718, 
895 

Protozoa, first animals, 66 

**Psychic photography,” 583 

——-science, 567-596 

Psychical research, 569 

Psycho-analysis, 556 

Psychology, the science of, 541-563, 1080 

Psychometry, 581 

Ptarmigan, seasonal change of colouring, 
140 

Pterodactyls, 130, 131 

Pterosaurs, 99 

Puffin, the, sharing nest, 415 

Puffins, strange ways of, 979 

Punnettt, Prof. R. C., 187, 367, 381 

Putrefaction, action of Bacteria, 901 

Pycraft, W. P., 413 


R 


Rabbits, domesticated, 189, 1125 

——introduced to Australia, effect of, 654 

——remarkable breeds produced, 1126 

Races, black or negroid, 1095 

——decline and fall of, factors in, 1102 

——intermingling of, 1100 

——lost, 98, 1103 

——of mankind, primitive, 176 

——of mankind, how they arose, 175 

——“‘superior”’ ousted by ‘“‘inferior,”’ 

——the making of, 1099 

——white or Caucasian, 1095 

——yellow or Mongolian, 1095 

Racial differences, how accounted for, 1098 

Radio-active bodies, 27 

——elements, 253, 257, 265 

Radio-activity, 265 

Radiolarians, 67 

Radium, discovery of, 253, 256, 258 

Rain, how produced, 273 

Rainbow, the, 22, 787 

Ramsay, Sir William, discovers helium in 
minerals, 24 

Rare earths and their uses, 736 

Rats, destruction by, 655 

Rattlesnake, Huxley’s account of his voyage 
in the, 999 

Raven, wisdom of the, 409 

Rayleigh, Lord, 310 

Rayleigh, Prof., 266 

Rays, Alpha, 259 

——Beta, 259 

——Gamma, 259 

Reason and instinct, 80 

——and intelligence, 239 

Recording methods, 774 

Redi’s experiment, 880 

Reflex actions, 77, 208, 345, 544 


1100 


1210 Index 


Regeneration, 688 

——power of, in animals, 690 

——remarkable experiments, 691 

Rejuvenescence of animals, 696 

——process of, 72 

Relativity, the theory of, 1031 

Rennie, Dr. J., 302 

Reproduction, asexual, 68, 686 

——by budding, 685 

——by fission, 685 

——of life, 683 

—— parthenogenesis, 688 

——sexual, 68 

Reptiles, age of, 98 

——first, 96 

——first appearance of, 96 

——flying, 101 

giant, the waning of, 101 

——nmind of, 218 

——of the open sea, 980 

——of to-day, 1019 

Respiration and circulation, regulation of, 
1143 

Rhizopods, the, 67 

Rhythm, constitutional, in animals, 141 

Riddle, Professor Oscar, work of, 70 

Ritchie, Dr. James, 192, 194, 660 

Robber-crab, 128, 196 

Robinson, Dr. Louis, 159 

**Roc,”’ of the Arabian Nights, 398 

Rock Record of animals and plants, 88 

Rocks, chemically formed, 946 

——-story of the, 919-955 

Roéntgen, discovery of X-rays, 255 

Rook, the, 412, 445 

Root, the part it plays, 617 

Rotifer, the, 68 

Roundmouths, description of the, 1015 

Rubber, synthetic, 752 

Ruff, the, 436 

Rumination of the cow, 472 

Russell, Bertrand, The Analysis of Mind, 
548 

Russell, H. N., 38 

Rutherford, Sir Ernest, 253, 258, 259, 263, 
717 


S 


Saccharin, manufacture of, 753 

Salmon, story of the, 197 

Sand-crab, disguising itself, 148 

Sand-martin, the, 440 

Sandstone, the story of, 939 

Saturn, condition of, 32 

—w—its ten moons, 32 

——system of rings around, 32 

Saunders, Dr. Charles E., and wheat culti- 
vation, 191 

Scale insects, a pernicious pest, 656 

—— insects eliminated by lady-bug, 656 

Scalpel, 302 

Schoetensack, Dr., 169 

Schwalbe, Prof., 159 

Schwann’s experiments, 882 

Science, aim of, 1165 

——and feeling, 1175 

——and modern thought, 1165-1181 

——and life, 1179 


Science, limitations of, 1172 

——methods of, 1167 

——philosophy of science and religion, 1177 

——-scope of, 1169 

Science, Applied: 

——electricity, 763-818 

——flying, 843-864 

——wireless telegraphy and _ telephony, 
823-840 

Sciences, classification of, 1170 

Scientific symbols, 1169 

Scotland, extinct animals of, 192 

——introduction of domesticated animals 
to, 192 

——Neolithic man in, 193 

Sea, circulation in the, 968 

——colour of the, 973 

——denizens of the, 976 

——depths of the, 962 

——floor of the, 969, 983 

——life of the, 971 

——littoral area of the, 116 

——making of the, 959 

——movements of the, 966 

—— pressure in the, 964 

——science of, 959-987 

——-storms at, 968 

——temperature of, 963 

——uses of the, 975 

——why it is salt, 960 

Sea-anemones sting small fishes, 651 

Sea-desert, 122 

Sea-horses, disguises of, 146 

Seashore, a stimulating environment, 986 

Sea-squirts, their mode of life, 1014 

Seaweeds, changing light of, 993 

Seals, their mode of life, 984 

Seasons, biology of, 1045-1074 

Seed carried by clodlets, striking instances 
of, 647 

——functions of, 634 

methods of scattering, 1062 

Seeds, distribution of, 647 

**Selenium cell,’’ the, 41 

Sense, organs of, 73, 350 

Senses, evolution of, 541 

Serpents, the, 1021 

Sex, evolution of, 70 

Sexes, difference between, 70 

Sexual selection, theory of, 387 

Sheep, British breeds of, 1116 

——domesticated, their derivation, 1115 

——results of domestication, 1117 

Shelduck, the, 440 

Shooting star, 33, 35 

Shore-crab, camouflage of, 139 

Siedentopf, 310 

Sight, sense of, 351 

Silk, artificial, manufacture of, 754 

Silurian Period, 92 

Silver-plating, 722 

Sirius, 10 

Skin, a remarkable organ, 357 

——cells of, 682 

Skull, contents of the, 348 

Sky, blue, what it means, 280 

Slate, story of, 947 

Sleep, 1149 

——a puzzling phenomenon, 346 


ee ee 


Index 


Slipper animalcule, its tactics, 76 

Slosson, Dr. E. E., 748, 753, 760 

Smell, sense of, 351 

Snail, the, in winter, 1069 

Snake, egg-eating African, 220 

Snakes, destroying vermin, 658 

——mimicry of, 147 

Snipe, the, 438 

Soddy, Professor F., 258, 268, 272, 279, 727 

Soil fertilisers, 756 

Solar eclipse of 1871 and 1919, 18 

——spectrum, 22 

——system, 9, 11, 12 

——system, members of, 15 

Song of birds, 437 

Space and time (see Einstein theory), 1039 

Spallanzani, his animalcule demonstrations, 
881 

——work on luminescence, 994, 995 

Spectroscope, 15, 21, 50 

Spectrum, every substance has its own dis- 
tinctive, 51 

——how it identifies particular substances, 25 

Spencer, Herbert, 81 

Sperm-cells, nature of, 68 

Spider, cocoon of, 1059 

——flights of gossamer, 1064 

——nmigration of, 203, 1065 

——monkey, 464 

——rearing the young, 1059 

——tactics of, 145 

——water, 202 

Spiny ant-eaters, one of the lowest mam- 
mals, 453 

Spirillum, cause of cholera, 888 

Spontaneous generation, a long controversy, 
880 

—— its deathblow, 677 

——no evidence of, to-day, 62 

——theories relating to, 877, 882 

Sporozoa, 67 

Spring, biology of, 1048 

——flowers, 1049 

Squirrel, arboreal mode of life, 463 

——destroying wood-pigeon, 658 

——perfect table manners of, 464 

Starfish, a British, 119 

——Luida, 81 

Starling, Professor, 353, 356 

Starling, a story of the Military, 411 

Stars, age of, 38 

——analysed in the spectroscope, 37 

birth and death of, 42 

——composition of, 24 

distance from the earth, 13 

——distances between, 11 

——evolution of, 37 

—— great motion of, 44 

——how many are there? 12 

——position of, how ascertained, 50 

——variable, 41 

Steam turbine, ‘‘Parsons”’ type, 813 

Stellar universe, immensity of, 37 

St. Elmo’s fire, 993 

Stickleback, care of young, 119 

——fresh and salt water, 212 

——remarkable ways of, 1060 

Stoat, brown, seasonal change of colouring, 
140 


1211 


Stomach, work of the, 327 

Stone Age, 172 

Storage batteries and accumulators, 804 

Stork, the White, 438 

Storms, magnetic, 20 

Stratosphere, 765 

Struggle for existence, dominance of man, 
104 

——for existence on the shore, 117 

——for existence, reasons for the, 137 

**Subliminal self,’’ the doctrine of, 1088 

Sugar-making, 753 

Summer, biology of, 1056 

——intense activities of, 1056 

Sun, action of, 291 

——distance from the earth, 13 

——eclipse of, 12, 17 

——is it dying? 25 

——its tremendous energy, 25 

——knowledge of the, 16 

——photosphere, 17 

——prominences, 18, 20 

——source of its heat, 15 

——temperature of, 20 

——the, a star, 12 

——tides, 292 

Sundew, how it catches insects, 612 

Sun’s energy, explanation of, 26 

——light and heat, what failure of would 
mean, 279 

Sunspots and magnetic storms, 20 

——composition of, 274 

Surinam toad and its young, 128 

——-strange habits, 217 

Survival, evidence for, 589 

——of the fittest, 111 

Swammerdam, 303, 304 

Swedenborg, 579, 590 

Symbiosis, 120, 610, 652 

Synthetic chemists, 61 

System of nature, evolving, 105 


it 


Tacchini, Professor, 19 

Tailor-ants, the ways of, 511 

Tapeworms, story of, 662 

Taste, sense of, 351 

Teeth, described, 322 

Telepathy, discovery of, 571 

——instances of, 572 

Telescope, history of its construction, 47 

Temperature, uniform, 286 

Tentative men, 168, 171 

Termites, move in armies, 521 

——wonderful achievements of, 516, 521 

Tern, the White, 438 

Terrestrial life, risks of, 86 

Thermionic valve, 835 

Thomson, Sir J. J., 258, 263 

Thorndike, Professor, 233, 237 

Thought transference, experiments in, 571, 
573 

Throstle, song of the, 417 

Thrush, breaking snail shells, 224, 445 

——Miss Frances Pitt’s experiments with, 
446 

Thunderstorm, how caused, 273, 785 

Tidal energy, source of, 293 


1212 


Tides, influence of, 291, 292 

——rate of, 966 

Tiger Beetle, the ways of, 512 

Time and space (see Einstein’s theory), 1039 

Titan, moon of Saturn, 32 

Tortoise, 1021 

——Gilbert White’s, 219 

——the soft-shell, ways of, 218 

Tower, Prof. W. L., 378 

Toxins and antitoxins, 332 

Trade winds, 771 

Transmission of energy, 795 

Transmutation of elements, 726 

Tree-sloths, mode of disguise, 150 

——mode of progression, 463 

Trees, big, of California, 602 

Tropisms, meaning of, 78 

——plant, 619 

Trotter, Mr. Wilfred, 553 

Truth, goodness, and beauty, 1077 

Trypanosome and sleeping sickness, 66, 67 

Tuberculosis, open-air treatment of, 1148 

Turbines, water, 811 

Turtles, 1021 

——egg-laying, 196 

——fish-eating, 980 

——Professor Yerkes’ experiment, 219 

Types, ancient, cessation of a large number 
of, 98 

——ancient living representatives of, 98 


U 


Universe, ancient people’s idea of, 245 
——duration of, 9 

——finite or infinite, 42 
——foundations of, 245-295 : 
——fundamental entities of the, 282 
——is it a spiral nebula? 46 
——nature of the, 13 

——-scale of the, 12 

——shape of our, 44-47 

——stellar, 37 

——what it means, 14 

Uranium, 265 

Uranus, 10 


V 


Vaccination, discovery of, 1159 
Vampires, 466 

Variation and selection, origin of, 377 
——of animals and plants, Darwin’s, 388 
——theory of, 366 

Variations and mutations, 369 

—— heritable novelties, 110 

——how they arise, 378 

Vegetation, primeval, 65 

Velocity of light, 1039 

Venus, 31 

——not self-luminous, 31 

Venus’ Flower Basket, 124 
——Fly-trap, 78 


Vertebrates, differences between higher and 


lower, 97 
Vestigial organs of the human body, 320 
Vesuvius in eruption, 927 
Vibrio, germs of Bacteria, 871, 888 


Index 


Vibrionia, germs, 875 

Virchow, 305 

Vision, sense of, 351 

Vitamins, importance of, 1138 
——lack of, causes disease, 1139 
——products of the plant world, 1139 
Viviparity, 81, 82 

Voice, evolution of, 96 

——of birds, 436 

Volcanoes, cause of, 926 
——eruption of Vesuvius, 927 
——in the British Isles, 925 
Volvox, 67 

Vries, Prof. Hugo de, 372 
Vulture, sailing of the, 131 


Ww 


Wallace, Alfred Russel, 148, 366, 370 

War in the air, 855 

Warm-bloodedness, 
and mammals, 144 

Wasps, communities of, 528 

——digger, behaviour of, 513 

——how they kill insects, 1060 

——nest-making, 529 

——social, 528 

——solitary, 528 

Water, importance of, 60 

——required by the body, 1138 

Waterhen, 1421 

Water-power, 809, 814 

Water-spout, 969 

Watson, Prof. J. B., 432 

Waves, electro-magnetic, 276 

——of heat, 276 

——of light, 276 

Weapons, of insects, 504 

——of mammals, 474 

——of plants, 626, 627 

Weasel, story of the, 491 

Weather, changes of the, 764 

Weather lore, 788 

——-science of the, 763-789 

Web of life, Darwin’s vision of, 643 

——interlinked systems, 106 

Weir, Mr. Jenner, story of a caterpillar, 146 

Weismann, Prof. A., 375, 379, 384 

Whale, Right, the, 459, 977 

——Sperm, the, 459, 977 

——Toothed, the, 977 

——Whalebone, the, 470, 977 

What science means for man, 1077-1089 

Wheat, Marquis, 190 

——romance of, 189 

Whin, story of the, 611 

White, Mr. P. B., 302 

White, Miss Gertrude, experiments with 
fishes, 213 

Whitman, Prof., 207 

Will-o’-the-wisp, probable cause of, 993 

Wilson, Dr. A. E., 401 

Winds, trade, 771 

Winter, biology of, 1067 

——change of colour of animals in, 1068 

——how different creatures face the 
problem of, 1068 

——Nature’s preparation for, 1065 

——torpor of many animals, 1070 


prerogative of birds 


Index 


Wireless, aerial, 832 

——and aviation, 823 

——concerts, 824 

——and flying, 848 

——detection of icebergs, 826 

Wireless, electric valve, 835 

——guiding ships, 824 

——messages across the Atlantic, 823, 827 

——oscillations, damped, 831 

——oscillations, undamped, 832 

——stations, 826 

——telegraphy, discoveries and theory of, 
827 

——telephony, future of, 838 

Wohler, 745 

Woodpecker, the green, 420 

Woodpeckers, clever ways of, 224 

Wood-pigeon, destroying grain, 658 

——love-song of, 418 

Woodward, Dr. Smith, 170 

World outlook, the, 1078 


1213 


Worms, first invaders, 93 
Wright, Sir Almroth, 1158 


Xx 


X-rays, discovery of, 253, 255 
——length of, 281 

——value of, 256 

——what they are, 255 


ns 


Yak, the, of Tibet, 1114 

Yerkes, Prof., experiments with a frog, 216 
Yucca moth, 78 

Yung, Prof., 513 


Z 


Zoology, science of, 1081 
Zsigmondy, 310 


ILLUSTRATIONS 


A 


Adams, Professor J. C., 10 

Aegir on the Trent, 290 

Aerial motor-cycle, 844 

Aeroplane, looping the loop, 855 

—— passenger cabin of, 860 

——-positions determined by wireless, 825 

——the “‘Bristol”’ family, 849 

——Vickers “‘ Viking” amphibian, 860 

Air liner arriving at Croydon, 861 

Airship (R. 33), 861 

Albatross, 128 

Alligator, 227 

Alps, Pennine, 932 

Altamira Cave, engraving of bison, 172 

Ammonite shells, 942 

Ameeba, 61 

Anatomy, School of, by Rembrandt, 326 

Anemograph, wind-velocity records, 1772, 
7173 

Anemometer, the Robinson, 778 

Angelo, Michael, 1080 

Angler’s trap, the, 1014 

Animal behaviour, inclined plane of, 44 

Animalcule, 871, 906 

Animals, behaviour, inclined plane of, 76 

——chalk-forming, 65 

——genealogical tree of, 61 

——of Cambrian Period, 90 

——open-sea, colony of, 119 

Ant-eaters, 454, 478 

Antlers, growth of, in deer, 484 

Ants, attacking a snake, 513 

——shepherding green-flies, 1061 

Ape-man, the Java, 157, 164, 170 

Arab, an, 1098 

Archeopteryx, first known bird, 91 

Aristotle, 547 

Armadillo, Nine-banded, 485 

Arthur’s Seat, Edinburgh, 925 

Attention, 546 

Atmosphere, exploration of, 765 

Atoms and electrons, relative sizes of, 258 

——arrangements of, in a diamond, 267 

——disintegration of, 2701 

Auk, Great (with egg), 402 

Aurora Borealis, The, 20 

Avocet, bill of, 191 


B 


Bacteria, 870, 871, 876, 877, 882, 883, 888, 
889, 894, 895, 900, 901, 906, 907 


Badger, European, 490 

Balfour, Sir Arthur J. (now Earl), 570 
Balloon, pilot, 768 

Bamboo, cultivating, 624 

Banded Krait, 139 

Banyan-tree, 616 

Barberry, flowers of, 617 
Barnacle, a floating, 981 

Barrett, Sir William, 570 

Bat, “Long-eared, 472 

Bateson, Professor William, 368 
Bayliss, Professor (now Sir) W. M., 358 
Bear, Polar, 227 

Beaver, 220 

Beech-tree, roots of, 613 

Bees, 

——fertilization by, 645 
——Humble-Bee, hairs from, 644 
-——pollen basket on leg of, 524 
——sting of the Honey-Bee, 306 
——tongue of a Hive, 524 
Beethoven, 1081 

Beetles, burying, experiment of a, 645 
——Colorado, 658 
——Lady-Bird, 662 

——Mite on a Dor, 654 
——Wasp, 147 

—— Whirligig, leg of a, 192 
Bergson, Professor, 584 

Biceps, 342 

Biplane, Wright’s first machine, 844 
Birds, bills of, 191 
——Black-Cock at play, 427 
——Brown-Bird, 435 
——Chimney-Swift, 421 
——Crocodile, 649 

——Diver, Black-throated, 421 
——Edible Swift, 442 
——evolution of, 398 
——Flightless Toothed, skeleton of, 100 
——food and, 399 

——Golden Eagle, 406 
——Guillemots, 443 

——Gull, common, 420 
——Harpy Eagle, 216 

——Heron, 417 

——Herring Gulls, 406 
——Jackdaws, 416 

——Lapwing or Peewit, 420 

—— Magpie, 410 
——Meadow-Pipit, 416 
——Nightingale-Hen, 411 
——Owl, 434 

——Pheasant, Amherst, 424 


14 


Illustrations 


Birds, Pheasant, Swinhoes, 426 
——Puffins, 410 

——Raven, 407 

——Secretary, 407 

——Skuas, a pair of, 427 
——Sparrow, House, 410 
——Winchats, 411 

——wings of a, 91 

——and their food, 399 
——evolution of, 398 

Bison, Altamira Cave engraving, 179 
Bitterling, 124 

Bittern, 143 

Blackcock, 427 

Bladderwort, the, 1071 

Blood circulation, 327, 330 
——corpuscles, 327, 681 
Bloodhound, 1121 

Blood-Vessels of the human body, 338 
Blue cheese mould, 677 

Bluebottle, 667 

Bower-bird, Newton’s, 435 
“Boyhood of Raleigh” (by Millais), 546 
Bragg, Professor Sir W. H., 247 
Brain, 73, 157, 335 

Bramble, thorns of, 617 
Broom-pods, explosion of the, 1064 
Brownian movement, 251 

Bulldog, 1120 

Burt, Mr. Cyril, 555 
Burying-beetle, 645 

Butcher’s Broom, 601 

Butterfly, coiled proboscis of, 304 
——the Dead-leaf, 146 


——Wall, 309 
Butterfly Orchis, 629 

¢ 
Cables, armoured, 799 
Cactus, 628 


Cambrian period, animals of, 90 

Camels, “‘The Midday Halt,” 478 

Camomile, wild, 625 

Candle moulding, 757 

Cantonese gentleman, a, 1099 

Canyon, limestone, 60 

Canyon, sixteen mile, in Montana, 804 

Capstone Hill, Ilfracombe, 969 

Carrion-crow, strange nest materials of a, 
438 

Cassowary, 201 

Cat, wild, 659 

Caterpillar larva, 512 

Cat-fish, electric, 998, 1003 

Cells, cellular structure of cork, 870 

——collumnar, 870 

——diagram of Beginning of Individual 
Life, 72 

——from the human cerebrum, 684 

——Heart of a pine-bud showing, 680 

——hexagonal, 870 

——in the lens of a chick’s eye, 681 

Cerebrum, human, 684 

Chameleon, the Warty, 140 

Cheetahs, 238 

Chiasmodon niger, 120 

Chimney Swift, 421 


1215 


Chimpanzee, 156, 157, 161, 233, 238 
Chronoscope, 555 

Clavellina (“living backwards’’), 693 
Clerk-Maxwell, J., 246 

Cliffs of Dover, 947 

Clouds, 765, 769, 786, 787 

Clover, fertilisation by ‘bees, 645 
——wild white, 609 

Coal, products of, 745 

Coal-cutter, electric, 795 

Coast erosion, 925 

Cocker spaniel, 1121 

Coco-nut palms, 600 

Colorado Beetle, 658 

Coloration, protective, 138, 141, 142 
———-seasonal, 141 

Colours, rotating disc for mixing, 283 
Columnar cells, 870 

Comet, 33 

Copper-ring and electro-magnet, 800 
Coral, 948 

Coral fish, 980 

Cork, cellular structure of, 870 
Cormorants, 662 

Cows, Highland, 1113 

Cox’s Caves, Cheddar, 927 

Crabs, 147, 193 

Cricket, Mole, 312 

Crocodile, Indian, 1015 
Crocodile-bird and its reptilian partner, 649 
Cromagnon man, 178 

Crookes, Sir William, 247 
Cuckoo-pint, 632, 633 

Cuckoo-spit, 147 

Curie, Mme. Sklodowski, 716 
Cuttlefish, 116, 118 

Cuvier, Baron, 86 

Cynodont, skull of, 454 


D 


Dalton, John, 716 

Dante, 1085 

“Dark Matter,” a nebula region south of 
Zeta Orionis, 37 

Darwin, Charles, 56 

**Darwin’s point,” 160 

Davy lamp, 757 

Davy, Sir Humphry, 729 

Death’s head hawk-moth, 512 

——pupa of, 512 

Deep-sea deposits, 975 

Deer, 484, 485 

Deerhound, Scots, 1120 

Diamond, the Cullinan, 734 

Diamond mines, Kimberley, 952, 953 

Diatom, 318, 704 

Dingo, 216 

Distillation of orange blossoms, 752 

Diver, black-throated, 421 

Dodder, 609 

Dodo, model of extinct, 398 

Dog, Alsatian Wolf, 226 

——Wild, 216 

Dor Beetle, 654 

Dormouse, 491 

Dover cliffs, 947 

Dowsing, art of, 585, 593 


1216 


Dragon-fly, 507, 705 
Duckmole (duck-billed platypus), 95 
Dyes from shells, 746 


E 


Eagle, Golden, 406 

——Harpy, 216 

Ear, human, 160, 353 

Earth, representation of strata of, crust, 92 

Earthquake, effects of, 920, 921 

Earthworms, 72, 644 

Echidna, 454 

Eclipse of the moon, 14 

Eddington, Professor, 10 

Edible Swift, 442 

Edison, Thomas A., 794 

Eel, electric, 998 

——life-history of, 200 

Einstein, Albert, 1153 

Elbow-joint, 342 

Electric catfish, 998, 1003 

——coal-cutter, 795 

——dead-man’s handle in, trains, 807 

——discharge in vacuum tube, 258 

——eel, 998 

——“‘flier’’ crossing the Rockies, 812 

——incandescent lamp, 817 

— —lines of force, 825, 828 

—-—locomotive, 813 

——overhead conductors, 800 

——power station, 803 

——railway, 802 

——Ray from the Mediterranean, 1003 

——rotary converters, 806 

——spark, 271, 274, 828 

——-storage batteries, 806 

——train, 801, 802, 808 

—-—transporter bridge, 802 

Electrical attraction between common ob- 
jects, 271 

Electrified yards at Butte, 809 

Electro-magnet and copper ring, 800 

Electro-plating, 723 

Electrons, apparatus for counting, 263 

——produced by X-ray movement, 262 

——streaming from sun to earth, 259 

——theory of, 267 

Elements, chemical combinations, 717 

Elephant, Indian, 484 

Elephantine Tortoise, 1018 

Embryology, experimental, 689 

Energy, transformation of, 287 

Engines, aero and locomotive, 854 

Eskimo, a typical, 1099 

Ether disturbance, an, 275 

——Michelson-Morley experiment concern- 
ing the, 1030 

Everest, Mount, 924 

Evolution of horse, 101, 104 

Evolution of human body, “‘ Darwin’s Point” 
on human ear, 160 

——hand of man and flipper of a whale, 157 

——homology, 105 

——skeletons of gorilla and man, 158 

——-skeletons of horse and man, 167 

——Skull of Java ape-man, 164 

——skull of man and gorilla, 161 


Illustrations 


Explosives, modern, 755 
Eye, cells in chick’s, 681 
——retina, 347 

Eye, long-sighted, 351 
——short-sighted, 351 
Eyeball in socket, 350 


F 


Falcon, attacking a Rook, 372 
——bill of, 191 

Faraday, Michael, 716 

Fern, spore-cases on, 685 
Fertilisation by bees, 645 
Fingal’s Cave, 926 

Fire-engine, chemical, 728 
Fire-fly, a tropical American beetle, 999 
Fishes, abyssal, 975 
——Chiasmodon niger, 120 
——coral, 980 

——deep sea, 120, 999 
——Electric Cat, 998, 1003 
——Gambian Mud, 91 
——Gold, scale from a, 313 
——Luminous, 995 
——Walking, 190 : 
Flammarion, Professor, 584 
Flat-worms, 685, 693 

Flea, 311 

——of rat, 656 

Flights, world’s greatest, 845 
Floating barnacle, 981 

Flower Basket, Venus’, 121 

Fly, Dragon, 705 

——Green, on flower, 662 
——House, 519 

——House, foot of a, 318 
——House, Proboscis of, 302 
——lIchneumon, 506 

——photo taken through eye of a, 307 
——-surface view of the eye of a, 308 
Flying, 87 

Fly-trap, Venus’, 77, 612 
Font-de-Gaume cavern, 179 
Foodstuffs, uses of, in the body, 1134 
Foraminifera, 65 

Fossil specimens, 943, 946 
Fowl, Japanese Long-tailed, 376 
Fowls, combs of, 377 

Fox, 496 

Fox-terrier, wire-haired, 1121 
Freud, Professor, 547 

Frog, life-history of, 192 
Fungus, 663 


G 


Gannet, 403 

Garden of Gethsemane, destructive locusts 
in, 532 

Genealogical tree of man and apes, 165 

Germinal continuity, 381 

Geyser at Waimangu, New Zealand, 930 

Giant’s Causeway, the, 939 

Gibbon, 161, 166 

Gipsy Moth, 658 

Giraffe and Okapi, 74 

Glacial action, 938 


Illustrations 


Glacier in the Alps, 936 

——valley, a typical, 937 
Glow-worms illuminating herbage, 998 
Goat’s-beard, 632, 648 

Goethe, 1084 

Gold-fish, scale from a, 313 

Goodsir, John, 305 

Gorilla, 158, 161 

Gossamer, spider’s, 202 

Grafting, methods of, 636 

Great Ant-eater, 478 

Skuas and their young, 427 
Greenflies shepherded by ants, 1061 
Greenfly multiplying on flowers, 662 
Group of the orders of living mammals, 454 
Greenland Whale, 118 

Guillemots, 443 

——eggs of, 438 

Gulf Stream, 974 

Gullet, 319 

Gulls, 466, 420 


H 


Harvey demonstrating blood circulation, 
327 

Hawk-moth, 143, 512 

Hazel stems and honeysuckle, 666 

Head and trunk, human, 346 

Heart, human, 327, 331 

Hedgehog, 490, 491, 663 

Hell Bay, Scilly Isle, 966 

Heredity in willows, 380 

Heron (with young), 417 

Hesperornis, skeleton of, 100 

Highland cows, 1113 

Himalayas, showing Mount Everest, 924 

Hindu, a, 1098 

Hip-joint, 342 

Hippopotamus, 497 

Hoatzin, 82 

Home, Daniel Dunglas, 571 

Homology, what is meant by, 105 

Honesty, dry fruits of, 649 

Honeysuckle and hazel stems, 666 

Hopkins, Professor F. Gowland, 1135 

Hornbill, bill of, 191 

Horse, evolution of, 101, 104 

——Mongolian wild, 1108 

——skeleton of, 167 

Horse-chestnut, arrangement of leaves, 608 

bursting its bud-scales, 1054 

fruits forming, 1054 

——fruits developed, 1055 

——leaves in resting position, 1055 

House-fly, 519 

Hunting Spider, the, 1061 

Huxley, Professor Thomas H., 86 

Hydra, green, 72 


I 


Ice, “‘boiling”’ a kettle on, 287 
Iceberg, 980 

Ichneumon-fly, 506 

Indian crocodile, 1015 
Indian, The Red, 1094 


1217 


Individual life, beginning of, 37 
Insects at rest, 1060 

Life, 510 

Irish coast erosion, 925 

Iron, molten cast, 722 

‘Isle of Wight disease,’’ 300 


J 


Jackdaw, 208, 416 

**Jacob’s Rod,’’ 592 

James, Professor William, 547 
Jasmine, gathering, 747 
Java-Man, 168 

Jenne, Dr., statue of, 322 
Jerboa, 473 

Jew, a, 1099 

Jupiter, 23 


K 


Kangaroo carrying young, 83 
Keats, John, 1081 

Keith, Professor Sir Arthur, 161 
Kelvin, Lord, 56 

Kimberley diamond mines, 952, 953 
Kind against kind, struggle of, 657 
Kivvitar, Castles of, 948 

Kiwi, 201, 402 

Krait, banded, 139 


L 


Lady-bird Beetles, 662 

Lamp Davy, 757 

Lampreys, marine, 120 

Lamprotoxus flagellibarba, a 
luminous fish, 995 

Landseer, ‘‘A Naughty Child,” painting by, 
554 

Laplace, 10 

Lapwing (or Peewit), 420 

Lavoisier’s respiration experiments, 7744 

Leaf from a city tree, 1152 

Leyden jar, 825 

Lichen, common British, 655 

Liebig, Justus von, 729 

Life, abundance of, 704, 708 

——beginning of individual, 72 

——insect, 510 

Light, speed of, 283 

——waves, 279, 282 

Lightning flash, 278 

——fork, 801 

Liquid converted into solid, 717 

Lister, Lord, 359 

Little Owl, 437 

Liver-fluke, 666 

**Living backwards,” 693 

Lizard, Australian species, 139 

——frilled, 202 

Locust, Asiatic, 533 

Locusts, destruction by, at Garden of Getb- 
semane, 532 

Lodge, Sir Oliver, 570 

London, a bird’s eye photograph, 849 

Lungs of man, 335 


remarkable 


1218 


M 


Magnet, 279, 282 

Magnetic circuit, 279 

Magpie, 410 

——moth, 369 

Mammoth, Font-de-Gaume cavern drawing, 
179 

Man and anthropoid apes, 161 

——Cromagnon, 178 

——hand of, 157 

jaw of Heidelberg, 171 

——Neanderthal, 175 

——Piltdown, 174 

——Pithecanthropus (the Java ape-man), 
157, 170 

——restoration of Rhodesian, 176-177, 178 

—— skeleton of, 167 

——skull of, 164, 178 

Manx Loaghtan ram, four-horned, 1117 

Maori, a, 1098 

Marconi Radio Berne, New Berne station 
of, 832 

Marine erosion on Irish coast, 925 

Mars, 23, 29 

Mastiff, 1120 

Matter, detecting small quantities of, 254 

Matterhorn, the, 933 

Maxwell (see Clerk-Maxwell) 

McDougall, Dr. William, 547 

Meadow Pipit, 416 

Mendel, Gregor, 368 

Mendeleeff, 735 : 

Mendelian inheritance in fowls, 385 

——in wheat, 381 

Mendelism in mice, 384 

Mendel’s law illustrated in peas, 380 

Metchnikoff, 676 

Meteorite, 57 

Meteors, 22 

Michelson-Morley experimental apparatus, 
1030 

We Wonders of, frontispiece, Vol. 
I 


Milky Way, 14 

Millais, ‘‘The Boyhood of Raleigh,” paint- 

ing by, 546 

Million, what is a?, 250 

Missel-thrush, 426 

Mite, Dor beetle, 654 

Mole, 461, 466 

Molecules, 250 

Monaco (the late), Prince of, 962 

Mongolian wild horse, 1108 

Monitor, the variable, 139 

Monoplane (D. H. 29), 844 

Moon, at nine and three-quarter days, 29 

——craters of, 28 

——diagram of a stream of meteors showing 
the Earth passing through them, 32 

——eclipse of, 14 

——map of, 29 

——map of the chief plains and craters of 
the moon, 32 

More-pork, Australian, 190 

Mosquito, life-history of, 518, 519 

Motks, eggs of, 301 

——Gipsy, 658 


Illustrations 


——-Hawk, 143, 512 
Magpie, 369 
——Yucca, 76 
Motor-cycle, aerial, 844 
Mountains, 924, 931 
Mouse, Harvest, 497 
Mud-skipper, 190 
Murray, Sir John, 962 
Muscle fibre, 334 
Muscles, 343, 354 
Mussel, Freshwater, 650 
Myers, F. W. H., 584 
Myxcedema, treatment by thyroid extract 
696 


N 


Nature’s chemistry, 745 
*“Naughty Child, A”’ (by Landseer), 554 
Nautilus, the Paper, 117 
——the Pearly, 186, 187 
Neanderthal man, 175 
Nebula, Giant Spiral, 41, 56 
Great, In Andromeda, 15 
Great, In Orion, 40 
Spiral, Seen Edge-on, 44 
Nebula region south of Zeta Orionis, a, 37 
Nerve-cell (or neurone), 346 
Newt tadpoles, 692 
——twins artificially produced, 689 
Niagara Falls, 286, 816 
Nightingale, 411 


O 


Oak-tree, section of, 601 

Obelia, 68 

Octopus, 116 

Okapi and Giraffe, 74 

Opossum, and young, 455 
feigning death, 208 
Woolly, carrying her family, 124 

Orang, 161, 166, 232 

Orang-utan, 232, 233 

Orchid, a highly evolved, 650 

Orchis, Butterfly, 629 

——Lady’s slipper, 629 

Oscillatory electric spark, 828 

Osler, Sir William, 1144 

Otter, 239, 496 

Owl, 437 


in 


Palm-willow, 1049 

Paper Nautilus, the, 117 
Paper-making, 754 
Pariasaurus, 94 

Pasteur, Louis, 676 
Pearly Nautilus, 186, 187 
Peas, Mendel’s law illustrated in, 380 
Peewit, 420 

Pelican, bill of, 191 
Penguin, 213 

Pennine Alps, 932 
Perfumes, 752 

Peripatus, 83 


Illustrations 


Persimmon (after winning the Derby, 1896), 
1112 

Petrel, storm, 125 

Petroleum, natural well of, 756 

Petromyzon marinus, 120 

Phagocytes, 1152 

Pheasant, 424, 426 

Photosphere, 18 

Pigeons, Carrier, 212 

evolution of domesticated, 1124 

——Homing, 212 

Piltdown man, 174 

——-skull, 170 

Pine-marten, 659 

Pine-wood, annual rings of growth in, 1048 

Piper, Mrs., 571 

Pithecanthropus, 157, 164, 170 

Pituitary gland, effect of removal of dog’s, 
696 

Planets, relative dimensions, 11 

Planets, types of frontispieces, Vol. III. 

Polar Bear, 227 

Polecat, 491 

Pollen-grains, 688 

Pollination effected in ‘‘ bee-flowers,”’ 645 

Pond life, 677 

Pony, Shetland, 1109 

Praying Mantis, 138 

Precious stones, 950 

Prehistoric drawings, 179 

Prince of Monaco (the late), 962 

Protective colour resemblance, 138, 141, 142 

——form resemblance, 143, 144 

Proterospongia, 69 

Proteus, or Olm, 1014 

Prothalli, 685 

Protoplasm, 680, 870 

Protopterus, 53 

Pterodactyl, fossil of, 94 

Puffin, 191, 410 

Python, 1019 


R 


Rabbit, 388 

Radium rays, 263, 266, 270 

Rainbow, the, 774 

Rainfall, annual distribution in British Isles, 
783 

“Raleigh, Boyhood of” (by Millais), 546 

Ram, Manx Loaghtan, 1117 

——Unicorn Barwal, 1117 

——Wallachian, 1116 

Ramsay, Professor Sir William, 735 

Rat, rejuvenating a, 697 

Rat-breeder’s triumph, a, 369 

Raven, 407 

Rayleigh, Lord, 571 

Reed-warbler’s nest, 439 

Reflex action in animals, 347 

“Reflex Arc,” diagram of the, 76, 684 

Regeneration, a flat-worm illustration, 689 

Rembrandt, School of Anatomy, by, 326 

Remezia, nest of, 439 

Reproduction by budding, 684 

Rhodesian man, 176-177, 178 

Richet, Professor Charles, 584 

Rose, thorns of, 617 


1219 


Rubber-tree, tapping a, 753 
Ruff, the, 389 

Ruskin, John, 1084 
Rutherford, Sir Ernest, 246 


S 


Salmon, leaping, 197 

——life history of, 196 

Saturn, 23 

Scheme of levels of study, 305 

Scientific motion study, 1145 

Scots deerhound, 1120 

Sea, scene in the great depths, 119, 963, 
968, 981, 994, 996 

Sea-anemone, glass model of, 72 

Sea-cucumber, 119 

Sea-horse, 120 

Sea-pen, 1002 

Sea-urchins, 309, 709 

Seal, 460, 461 

Secretary bird, the, 407 

Seismograph, 924 

Semotilus, egg depositing by, 121 

*‘Sensitive plant,” the, 625 

Shetland pony, 1109 

Ship at sea, motion of, 1031 

Shoebill, 187 

Simpson, Sir James Young, 359 

Skin, section of human, 350 

Skuas and their young, 427 

Skulls, 164, 170, 178 

Slate quarry, 949 

Sloth, 466 - 

Smooth New Tadpoles, 692, 693 

Snails, inheritance in, 388 

—-—laid up for the winter, 1060 

Snake, the Banded Krait, 139 

Soa ewe, 1116 

Soap Bubble, A, 252 

Soddy, Professor Frederick, 716 

Solar prominences, 18, 19 

Solar System, diagrams of the, showing the 
relative distances and dimensions of the 
planets, 11 (in earlier printings see pages 
11 and 22) 

Sori or spore-cases on fern, 685 

Sound and space, 1031 

Space and time, 1031 

Spaniel, Cocker, 1121 

Sparrow, House, 410 

Spectra, stellar, 36 

Spectroscope, 24 

——modern direct-reading, 49 

Spiders, 77, 146, 303, 620, 1061 

——Gossamer, carpet made by, 202 

—— Water, 203 

Spoonbill, bill of, 191 

Spotted turtles fighting, 1018 

Squirrel, 87, 467 

Stags, fighting with their forefeet, 480 

Stallion, an Arab, 1109 

Star cluster in Hercules, 37 

Starfish, 116, 117 

Starling, Professor E. H., 358 

Star-ray curve, foundation of Einstein’s 
theory of gravitation, 1030 

Steel, piece of magnified, 313 


1220 


pba screen for recording temperature, 

tar 

Stickleback, 209 

Storm Petrel, 125 

Storm track map of North Atlantic, 782 

Struggle of kind against kind, 657 

Submarine cable, laying a, 798 

Summer, 1070 

Sun, the visible surface of the, 19 

——the main lay ers of, 18 

——photographed in the light of plone 
hydrogen, 19 

——February 5th, 1905, 22 

——See also Solar 

Sundew, 612 

Sunshine, daily duration, 779 

——recorder, 778 

Sun-spots, 22 

Swedenborg, Emmanuel, 571 

Swift, 421, 442 


T 


Tadpoles, 689 

Tapir, of Sumatra, 479 

Teasel, the wild, 1064 

Telepathic drawings and photographs, 574, 
575, 580, 581 

Telegraphy, wireless, 837. 

Telepathy: drawings by agent and repro- 
ductions by recipient, 574, 575 

——experiments at a distance: photographs 
and drawings, 580, 581 

Telephony, wireless, 836 

Telescopes, Mt. Wilson 100-inch, 45 

——Yerkes, 48, 49 

Temperature, variability of, 782 

Termites, Queen of, and her court, 524 

Thermionic valve, 836 

Thinker, The, 542 

Thistle, Carline, 633 

Thomson, Professor J. Arthur, 1135 

Thomson, Professor Sir J. J. 262 

Thought, measuring speed of, 555 

Thrush, 221 

Thumb-print in wax, 310 

Tides, 290, 291 

Time and space, 1031 

Tissue, vegetable, 870 

Tit-mouse, the Penduline, 439 

Toad, Surinam, 125 

Tooth, human, 319 

Torpedo ocellata, 1003 

Tortoise, Elephantine, 1018 

Tosa Fowl, 376 

Tree, banyan-, 616 

——beech-, 613 

——surgery, 637 

Trees, big, of California, 604 

——nminiature Japanese, 613 

Treves, Sir Frederick, 1144 

Triceratops, 95 

Trilobite, 90 

Trypanosoma Gambiense, 69 

Tuatera, the, 1015 

Turbine, steam, 817 

Turner, J. M. W., R. A., 1085 

Turtles, spotted, 1018 


* 


Illustrations 


U 


Unicellular plant, 318, 677 
Unicorn Barwal ram, 1117 


V 


Vacuum tube, electric discharge in a, 258 
Vein valves, 331 

Venus’ Flower Basket, 121 

——Fly-trap, 77, 612 

Vesuvius in eruption, frontispiece, Vol. IV. 
Vixen, with cubs, 496 

Volvox, 69 


W 


Walking fish, 190 

Wallace, Alfred Russel, 570 

Wallachian ram, 1116 

Wasps, 300, 525 

Water, natural changes, 728 

Water-lily, Giant, of the Amazon, 605 

Water-spider, the, 203 

Waterspout, 974 

Water Track, a six-pipe, 748 

Waves, electric, 828 

——light, 282 

Whale, flipper of, 157 

——Greenland, 118 

Wheat, Mendelian inheritance in, 381 

Whelk, 305 

Whinchats, 411 

Willow, the ‘‘palm” or “‘pussie,”’ 1049 

Willows, heredity in, 380 

Windpipe, 335 

Wine yeast, 734 

Winter, 1065 

Wire-haired fox-terrier, 1121 

Wireless telegraphy and telephony, lines of 
electric and of magnetic force, 828 

——listening in, 824 

——Morse Code, 829 

——receiving-room, Towyn, 824 

——signals, 825 

——station at Carnarvon, 829, 837 

——telegraph and telephone in an aeroplane, 
848 

Woodpecker, 217 

Wood-sorrel, 628 

Wright, Sir Almroth, 1153 


xX 


X-ray movements producing electrons, 262 
——photographs, 254, 255 


Y 


Yak, domesticated form of the wild, 1113 
Yeast plant, 734 
Yucea moth, 76 


Zoophyte, 68, 667 
Zulu, a, 1098 


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